The Caesar. The Rachel. The Twiggy. Celebrities often set trends for hairstyles that weave their way into popular culture for a minute or two. Since Brigitte Bardot and Lucille Ball popularized poodle perms and beehives in the ’50s, society has looked to Hollywood for the next big thing in hair. Good or bad, they’ve dictated family photos and school portraits for decades and helped us all look back and say, “What was I thinking?”

On the other hand, some have stood the test of time and, with a few slight modernizations, still appear on red carpets and sidewalks alike. Which ones are hairdos and which ones are hair don’ts? You be the judge:

1. Bo Derek and her beaded cornrows from 1979’s 10

2. Farrah Fawcett’s long, feathered locks

3. Cher’s long, straight, center-parted hippie hair

4. Dorothy Hammill, who brought The Wedge to the masses

5. Jennifer Aniston, whose character on Friends was the envy of women everywhere

6. Meg Ryan and her cropped, tousled curls found their way into salons in the ’90s

7. Madonna’s teased and crimped-beyond-recognition mane circa “Like a Prayer.”

8. George Clooney’s straight forehead fringe, nicknamed The Caesar

9. Christina Aguilera’s Xtina phase that brought about stick-straight black hair with a blonde top layer

The stylists behind these celebrities’ do’s marked their place in history and pop culture forever by going out on a limb and trying something new. Imagine how it would feel to see one of your styles on TV or even in the aisle next to you at the store. What will be the next big look? One can only imagine.

Most fashion trends come and go, but some looks are so timeless they will always find their way back in style. Here are 6 retro hairstyles that will always be hot:

1. The mop-top: From The Beatles to Bieber, this floppy style isn’t going anywhere. It’s hard to believe that 50 years ago this was considered long hair for boys. Shaggy bangs and covered ears are the trademark of this cut. The length in back is negotiable – but don’t go too far, you might wind up with an accidental mullet!

2. Bangs: The 70’s would have been boring without Farrah Fawcett and her signature feathered power-bangs. It’s true, bangs aren’t what they used to be, but they’ve managed to stay relevant. Actresses such as Zoe Deschanel, Christina Ricci and Reese Witherspoon use their bangs as subtle accents to their other notable features.

3. Spiked: Sid Vicious and the rest of the Sex Pistols were every mother’s nightmare in the late 70’s. Spiked hair, black leather, tight pants – skinny jeans, anyone? – were the hallmarks of this style. Nowadays parents accompany their children to Green Day concerts and ‘faux hawks’ are acceptable in corporate culture. Who knows what Sid would be doing if he were alive today. An American Express spokesman, perhaps?

4. Pixie: This cropped cut was born in the 1920’s and worn by rebellious women known as ‘flappers.’ In 1968 Mia Farrow revealed a horrific take on the pixie cut in the film ‘Rosemary’s Baby.’ And in 2001 this look made an adorable cinematic return on the scalp of Audrey Tatau in the film ‘Amelie.’ Who’s been seen sporting this look lately? Katie Holmes, Rihanna, Emma Watson and former Spice Girl Victoria Beckham, just to name a few.

5. Pompadour: Before Twilight’s Edward Cullen swooned Bella Swan and became the obsession of every teenage girl (and most of their mothers), Elvis Presley drove the ladies crazy with his gyrating hips and greased signature ‘pomp.’ This high jutting style took a wildly experimental turn in the 80’s on the heads of such bands as ‘Flock of Seagulls’ and ‘Duran Duran.’ And who could forget the competing pomps sported by Dylan McKay and Brandon Walsh on the TV show 90210 in the 90’s?

6. Bed Head: Who says style has to be intentional to be timeless? This devil-may-care do has been around since the earliest cave dwellers and has never looked back. Just think how history might read differently if Albert Einstein had spent more time combing his hair than helping the Allies build the atom bomb. One thing’s for sure, Nick Nolte’s mug-shots wouldn’t be nearly as priceless if the photographer gave him a brush and some gel.