who....

Sorry. Got a bit excited at the prospect of time alone with a certain Mr. Black.
For all round general survival: Dumbledore
For intelligent conversation: Hermione and Remus (with a whole loada wolfsbane potion)
For protection: Harry and Hagrid
For a laugh: Fred and George
For a challenge: Severus
For populating the island: SIRIUS (sorry guys)

Ummmm what else?

ummmmm Becca!

As much as I like my previous choices, I think that I might just have to change my answer to Dobby. Having someone around that's able to cook is certainly appealing, and I wouldn't want to deal with the sometimes overbearing moterliness of Mrs. Weasley.
I'm doubtful that Hermione or Remus are very good cooks, but I wonder exactly how well Harry is able to, and if Severus, as a Potions Master, would be a decent cook...

("For populating the island": Roflmao!!)

Hegrid and I would get along great - but I'd actually pick Luna, because we would keep each other entertained while still surviving (can you imagine the Swiss Family Robinson style house Luna would come up with??!!!) LOL

Becca, I'm sorry, but that was wrong on so many levels...

Nah, it's not.
You just have to time-travel and grab the age-appropriate one, roflmao.
Preferably a Pre-Azkaban one. *Nods*

I never understood the Sirius attraction... can someone clue me in? What did JK say/describe that was so attractive?
*busy building my three story hut with Luna*

I dunno. I think partly it's just the Marauder appeal in general, but obviously James is definitely spoken for, and Remus lovers are a bit more quiet.
The motorbike, I guess, and what it symbolizes. It gives Sirius a very-handsome-suave-intense-rebel image.
And at the same time, on the other hand, he has the whole "dark family childhood" angle working for him, you know, the secret insecurity and -supposed- sensitivity. (As if.)
Oh, yeah, and he's also older/more mature?, which supposedly eliminates some of the drawbacks of Harry or Ron (as in their complete cluelessness and thickheadedness when it comes to the opposite gender).
*Rubs chin* Yup, I think that about covers it. I'm done with my analyzation now.

Oh, wait. Here's the answer in one word, I think:
FANFICTION.
Roflmao. XD

Thank you - that really did help! I never got the attraction because all I could see was the screaming face from the newpaper....
I would love to have Hedwig on my island too (poor little bird, didn't get treated fairly in the last book)

Well, that's why so many people (okay, mostly girls or women) hate the movie Sirius, because even though Gary Oldman is a good actor he's just not hot enough for fanfiction! (and possibly canon) Sirius.
Roflmao.
Poor Hediwg. I'd still have to say Dobby though, I think. :/ (Sorry, I can't resist the FOOD.)