I'm not the best at writing stories, but if you're writing about a hacker...
MAKE SURE HE HAS A REAL LIFE!!!!!!!!
"Hacker's" nowdays simply mean "computer literate folk"... and this is the future you're writing about. Maybe this guy weight lifts, thats why he's so badass riding his bike with his lappy in his backpack. Or maybe he likes running alot, and every morning he'd go for a jog around the city. Go to a friend's house and shower off or whatever.
Maybe he lives with his girlfriend who's providing for him? Hoping he'll "Make it big someday"... just an idea. Play around with this. But he must not in any way be socially inept. Because, thats just retarded.
Read ALL you can about Adrian Lamo (it'll help you with this story tons)
http://www.google.com/search?q=adria...utf-8&oe=utf-8
As for his laptop. It should most likely NOT be top-of-the-line. This guy lives on teh streets, he has no money for such fancy crap. He should be very mediocre in the begenning of this story, and turn out pretty badass during the end (either with tons of money, or a new lifestyle, or both, or he just solved a puzzle or something, I dunno...).
And there has to be a reason he knows all of these skills, or how he got into computing and didn't turn out to be such a lowlife bum. Maybe he still gets high/drunk with friends? Smokes cigs - that'll give some life to this character.
*yawns*...i'll write more later
