well, since its all spread around, ill sum some things up for you and imput my knowledge
that being said, i have a mac book with the 2.0 ghz core duo in it with the 120 gig hard drive and 1 gig of ram. running xp pro. but for some reason my boot camp is messed up. i still can boot it though.
i also have a desktop i custom built myself that would blow your mind. i promise. but thats not our subject.
first of all get more ram than 512 megs, the new windows vista reccomends atleast a gig or it, the new mac os is going to be the same way, i chose 1 gig cause i didnt want to spend the money for 2 gigs quite frankly.
when choseing a processeor what you have to do is realize that if you have a core duo processor it is going to have 2 cores so a possible processing speed of up to 4 ghz. now if that has hyper threading in it loke the core 2 duo processors do then it has a possibility of 4 logical processeors and 8 ghz possible logical processing speed. i dont remember if you can get that processor in there, it smokes tho.
the graphics card is not to good, its only 128 megs. in my desktop i run dual monitors and have 2 bridged 512 sli cards. dont expect it to show up with stuff realy nice. look for it to be average. built in gpu's are notorious for being slow in lap tops because the front side bus of the actual computer is so slow and most gpu's run faster than the motherboard they work with.
if you do intend to edit video i reccomend that you get the 120 gig hard drive. my roomate uses final cut all the time cause he edits for 2 plank and he is always having storage problems on his imac cause he doesent have enough hard drive space. i would reccomend an external hard drive though if you do edit, its just a good edition to the set up.
i think that about covers it, but if you have any more questions feel free to ask, im cisco a+ certified so i can go way way more in depth on a lot of these if you want.