A pretty face and a nice pair of D cups go a long way, but you can never underestimate the power of the booty. Heck, if it weren't for nice, firm butts, rappers would be stuck singing about...feet? So which celebrities are little in the middle but they got a nice back? And which stars need some butt implants - or lipo - stat? We separate the bootylicious from the booty vicious.

Jessica Biel

It's a given that Jessica Biel will wind up on every single "best of" body list. And though we secretly hate her, we've got to admit that Biel has a rear end that'll make a man stop in his tracks and say, "Daaaamn!" Or, as TMZ.com puts it, "Jessica Biel's badonkadonk stretches fabric and strains credulity."

What's her secret? Biel's personal trainer, Jason Walsh, tells FitSugar.com that Jess loves to do walking lunges. "This stretches the larger leg and glute muscles," he says.

Jennifer Lopez

Oh, you knew Jennifer Lopez was going to be on this list. Even, she's fascinated by that ample rump, telling the New York Post that one "could serve coffee using my rear end as a ledge." Lopez has denied rumors that she's had her famous derriere insured for one billion dollars, telling the BBC, "I don't know where they got it from. When I heard the story I thought it was very funny."

Kylie Minogue

Pint-sized pop diva Kylie Minogue is famed for her perfect booty, but eyebrows were raised when, according to FemaleFirst.co.uk, she recently bragged, "Look at my butt. I've got a great black girl's butt, kinda like Beyonce and J.Lo. I may be from Australia but I think I must have some blackness in me. You'll never hear me wishing I had a smaller butt. The bigger the better."

Maybe she's right to brag. After all, Smh.com.au reports that her keister is one of the most requested when women go in for butt implants.

Beyonce

Are you ready for this jelly? Unsurprisingly, the woman who brought the world "Bootylicious" has a shapely, curvaceous bottom that puts all of those bony actress bums to shame. Like Jennifer Lopez, Beyonce is a great example of someone who works her voluptuousness to her best advantage.

Beyonce also makes our list for furthering the booty cause; thanks to her, "bootylicious" has been added to the dictionary, WireGirl.com reports. "I don't know what it says in the dictionary but my definition is beautiful, bountiful and bounce-able," Beyonce has said.

Cameron Diaz

There's just no pleasing some people. According to AzCentral.com, Cameron Diaz isn't all that crazy about her much-admired butt. "I want to be a big, fleshy voluptuous woman with curves," she says. "I want a big bum but I don't have one. I used to look at my bum and go, 'Aw'."

Spare us. Anyone who's seen a Diaz film - in which she frequently shakes her booty - knows that's she been blessed with an athletic, firm, nicely toned rear. Just ask Eva Mendes. TMZ.com reports that the sexy actress told Maxim that Cameron "has the cutest, tighest butt. Her butt is so cute I can't take it."

Anna Kournikova

Note to self: Take up tennis. Retired tennis player Anna Kournikova is better known for her backside than her back swing, but in an Elle column appropriately titled "Hind Sight," she lamented that she'd started to lose her sporty, tight bottom.

"Almost three years have passed since I was on the court full-time, and my body has changed again," she wrote last year. "Because I'm much less bulky now, I was worried I was losing the hardened junk in my trunk. I set up a goal of boosting my curves by increasing the muscles on my hips, paring down on my waist, and creating a bum you could use as a drink holder."

Heidi Klum

Want to sell some Jordache jeans? Put a topless Heidi Klum in a pair that perfectly hugs her shapely butt. Klum credits her flawless figure - after giving birth to three kids in as many years - to staying active. "We work in the garden," she says. "We climb in the tree house with the children. We are always mobile."

The Times of India also reports that Klum has husband Seal do a "butt check" to make sure she's looking fit. Lucky guy.

Halle Berry

We think Halle Berry has a gorgeous, curvaceous derriere, but she's actually not a big fan. Why? Because, according to ContactMusic.com, she had ex-husband David Justice's name tattooed on her butt cheek. Thankfully Berry was able to cover the tattoo, but she still has a blemished booty.

"I really wish I'd never had the tattoo in the first place," she says. "Clean, clear skin is always better."

Coco

Sir Mix-a-Lot would go into cardiac arrest if he caught sight of the giant booty belonging to Coco, wife of rapper/TV detective Ice-T. While we've got nothing against curves, Coco's in-your-face ass looks unnatural in its largeness - so unnatural, in fact, that MediaTakeOut.com took it upon itself to dig up an old photo revealing Coco with a smaller behind. Their findings? "Given the sizable increase in booty mass and robustness, the MediaTakeOut.com staff has determined that CoCo's booty is a fake."

Kirsten Dunst

As these photos reveal, Kirsten Dunst suffers from two major butt ailments: flatness and cellulite. How she managed to acquire both is a mystery, but that scrawny ass is definitely dimpled. We think Dunst should treat herself to a few doughnuts to fill out that frame. Kiki also made our "worst" list for having poor booty etiquette. TheSuperficial.com busted her scratching her butt, while StrangeCelebrities.com caught her flashing her crack. Get it together, woman!

Kim Kardashian

Aside from having a sex tape with Ray J. and being BFFs with Paris Hilton, it's hard to understand what exactly makes celebutante Kim Kardashian famous...until she turns around. Many have speculated that Kim's massive, shelf-like butt is the result of supersized implants, but she simply credits her Armenian heritage.

"Everyone now says I have a fake butt or butt implant," the New York Post quotes her as saying. "I'm Armenian; you should see all the women in my family. The women have bigger breasts and bigger butts. That's how I was born. I can't help it. I'm not gonna fight it. I definitely need to work out more and tone up, but I'm proud of my body."

Kirstie Alley

We'll give Kirstie Alley props for doing her Jenny Craig thing, and for having the guts to wear a bikini on Oprah (albeit with an icky body stocking). But when it comes to having junk in the trunk, Alley is practically a U-Haul. And she admits it, telling the Sunday Mirror that she's a "fat-ass mother." Alley is also the author of "How to Lose Your Ass and Regain Your Life." We eagerly await the sequel.

Teri Hatcher

There's nothing worse than a bony booty, and that's exactly what Teri Hatcher has got. We miss her curvier Superman days.

Funnily enough, Hatcher caused a stir when a video on TMZ.com appeared to show former President George Bush pat her bottom, which Bush of course denied. Writes ASocialitesLife.com, "I have a feeling he's telling the truth, because if that man's hand came anywhere near her bony rump, much less patted it, he certainly would have had at least one scratch to prove he'd touched that pointy tailbone of hers."

Serena Williams

We know she's a superstar tennis champ, and she probably works out ten hours a day, but Serena Williams has one scary booty. We give her props for maintaining such a fit, athletic physique, but her butt muscles are so large and defined that it's giving her a case of "bubble butt."

Quips StrangeCelebrities.com, "I've heard of tennis elbow before...but tennis butt?"

Tara Reid

Ay yi yi. First wardrobe malfunctions with her boob, now this. Can Tara Reid not hire somebody to make sure she's all covered up at all times? Her skinny bum is not something the public needs to see.

We think TheSuperficial.com summed it up best: "It's like somebody punched her in the butt as hard as they could and everything flew up into her chest. If she and Hank Hill had a kid, it'd have an ass so non-existent it would actually suck in matter. Like a blackhole, only less scientific."

Tara has had her fair share of plastic surgery issues, but maybe she'd reconsider and get butt implants?

Kate Bosworth

Missing: One butt. The very thin Kate Bosworth is practically a straight line from head to toe, resulting in the dreaded "no butt" syndrome. We'd love to see her return to her healthy Blue Crush figure...or invest in some Spanx.

BeyondHollywood.com had this to say: "Is that a butt or a flat iron board?"