i was in taiwan over the winter break. i went to the computer shopping district in the third largest city on the island to price out the motherboard, cases, and video cards (all which are manufactured in taiwan).
first thing i noticed was that all the stores seemed to carry only the low-end ati video cards. second thing was that the all of it is more expensive than what i can buy at newegg (including california sales tax). i ended up buying all my stuff in the states.
as for customs... well, are you coming through lax on the way back? i come through lax three or four times a year from taipei, and they never looked at me. it's not like i'm carrying thousands of dollars of stuff (or even hundreds, i guess), but they never, never bother me at all. i think it's just too busy for them to bother.
be smart. if they ask if you have food on you and you have gum, don't say you have gum. just say no. don't give them a reason to look at you.
if you're trying to get around customs, keep in mind that they only charge you for stuff you buy while you're gone. if you buy jewelry overseas, wear it home. if you buy an ipod, use it on the plane... do you get it? or mail it, i guess... that's completely legal from what i understand... or stuff it in a body crevice... or put the ipod in a condom and swallow it.
yeah.