Could be from a book, movie, Tv show, video game or whatever.
Me, I’d definately be Tony Soprano. He’s overweight, bald, and middle-aged, but still the coolest character ever.
Data from Star Trek: TNG.
Claire Fraser from the “Outlander” series.
mmmmm, Jamie Fraser goodness!
Without a moment’s hesitation… Pippi Longstocking! She was strong, fiercely independent, had a great sense of fashion ;), smart as a whip, ironically witty, lived alone and was friends with one very cool horse (who wouldn’t want that!!!). Oh, and street savy too.
Not to mention, her house was like a every kids’ dream come true. It was part jungle gym, part fort and part tree house, all rolled into one. She’s the absolutely freakin’ coolest. 
Besides, I love[d] the hair and freckles!
Well, I’d say I wouldn’t mind being Brynda al Keylan in the 3rd book of the Rune Blade Trilogy…sword-wielding and yummy kilted Kenzie Catfoot…puuuurrrrrrrrrrr
I suppose I wouldn’t mind being Sorcia(sp?) in Willow either (Val Kilmer was a rather yummy Madmardigan(sp?)…)
Katt in Breath of Fire II is also pretty nifty since I’ve always kinda wanted to be a kitty creature…
I also have to say being Sarah in the Labrynth would be pretty nifty… I wouldn’t have to change my name, plus I’d get to confirm that goblin kings have crystal balls… 
LOL
Bugs Bunny always seems to be having a good time. 
Xena, Warrior Princess. I never get a chance to kick ass in real life, so this would be a welcome opportunity.
I was asked that question about 10 years ago and I said Hal Jordan (Green Lantern), but that was before the whole Parallax thing.
Hagbard Celine from Illuminatus.
Skeeve from the Myth Adventures books.
Johnny Rico from Cafe Flesh.
Well, as long as we don’t mean people we really think are like us, I’ll go for Integra Wingates Hellsing from the anime Hellsing. She’s gorgeous, kicks butt, shoots cool guns, and gets to hang out with the likes of Alucard and Walter. I’d give up the cigar habit though.
If it has be somebody we think we could actually pull off being… geez, I dunno, a grown-up Hermione Granger I guess. But she’s braver than I am too.
Ed from Cowboy Bebop. Although she was nearly the only part of Cowboy Bebop I really liked… Or, Captain Tylor from Irresponsible Captain Tylor.
I’d definitely be John Blackthorne from the novel Shogun. I think that living in 16th Century Japan would’ve been an awesome experience. His was an incredible story, going from a shipwrecked barbarian to Hatamoto (retainer of the Shogun) and enjoying the spoils of such an honour.
Thought about this for about five minutes, and I must admit, Tony Soprano is a good choice there, DaPearl. He’s got money, family and friends (and singing fish) and he doesn’t seem to do much. I’ll pick either Tony or Frasier Crane. Frasier: Interesting job, sweet apartment and (what seems like) a pretty cool city.
Other honourable mentions:
James Bond - babes 'n gadgets
Bill Murray’s character in Groundhog Day (maybe not for too long, though)
Nanny Ogg. Lots of husbands, kids, likes a drink, likes another drink, her daughters in law do all the work, flies around on a broomstick, has a wonderful sense of humour, and has a cat that turns into a very handsome naked man on occasion. Oh, and Casanundra. Definitely Casanundra.
It would involve a slight sex-reassignment, but it’s a small price to pay - I’d like to be Simon Templar, the Saint. Preferably from the earlier books, but I’d settle for ‘as played by Roger Moore.’ He never ages, he’s rich, handsome, smart, funny, and a whizz with a gun, and most of all, he divides his time between being on vacation in exotic locales and the world of high crime. Without ever being prosecuted. Where can I sign up?
Either Sherlock Holmes or James Bond. Holmes most likely.
Scout Finch. Surely she grew up to be a remarkable woman, having a father like Atticus.
Maybe Astronaut Major Anthony Nelson, Jeannie’s Master, from I Dream of Jeannie.
You give me a Genie like her, make me her Master and I’ll take it from there.
Ghanima of Dune
Hawkeye Pierce of MAS*H
Professor McGonagall from the Harry Potter books. It would be such a neat world to live in, and she’s the sort of teacher I would like to be someday.
Why Keith Laumer’s Retief of course !
There has never been a cooler hero
Retief