ahh, what a thread.. so much nonsense to be added, but fuck all that, i'll give my honest opinion.
First of all, like a lot said, depends on how close u are, and the type of person they are, and what ur budget is.. I'll just go through some common shit
a) Music.. usually never a good option unless its some rare shit that he's been dieing to grab, and u take the time to find it and buy it
b) Gift Cards - if ur not close then, yes, its like giving money, but not really giving money. If you are close to the guy, personally every time i've received a gift card from a girl i'm tight with.. i'll look at them like "uhh thanks, but are u serious?" After knowing me this long u came up with a gift card?
c) Clothes - hahah NO, NO annnd NO... Unless u wanna go with him and grab him stuff u both like. Although that might piss him off as well (Although he might pretend it doesn't)
d) Electronics - meh, i'm not big on that shit, but i know guys that would love getting the new ipod touch or some shit. (problem with that is, its usually expensive)
e) Cologne - I figured this is pretty good, cuz fuck it a guy sitting around at home will never toss on cologne, but they will when they leave the house due to their exposure to the opposite sex, and why not something that appeals to them. Ur good with this unless u get something that they're allergic to or just cant stand
f) Making them something - If u don't know him well enough, hell no. If u do, it all depends on the type of guy he is. Personally if some1 goes through the trouble of making me something, I appreciate it more than anything else, even if its completely useless to me. Other guy's I know would be happier if u tossed him a $5 bill instead of staying up all night to make him something.
g) Tickets to an event - good, UNLESS he was planning on going to that event with his boys'.. 5 guys + 1 girl = a wack night
h) Wallet - HELL NO (maybe thats just me)
.. hope that give u a better idea.. again this shits way too subjective for an easy answer. At the end of the day, some dudes will appreciate just about anything.. others wont be satisfied, regardless of what u get em
peace