I haven't read all o fthis thread but heres my 2p, aside from suggesting a mac-top, if you can spec out a good one Dells do last pretty well, my dad has had his for ages and it seems pretty sturdy. They've also redesigned a few so they're probably not half bad.
avoid vista if you can, its terrible as it eats resources up like no one's business!
higher screen res is preferable too 1600x1000 sort of range for a WS 17" is worth aiming for, not the 1400x900, you get more photo on the screen that way.
As a word of advice if you call Dell and order over the phone you get through to Dell India, get chatty with the person who answers, maybe ask where they're from, and that that part of the world sounds great, you'd love to visit etc. - my mate did this and got
loads of extra stuff for free and a good deal on the original order too!...bit of flattery never harms