questions about Formatting a HD, plus repartitioning it.

ok so i'm about to format my hard drive and this is what i wanna do.

1) i wanna repartition it. i got 3 partitions on my 200 gb seagate HD right. 17gb for the startup Windows xp, about 50 for games and the rest for storage. i wanna repartition it for only 2 instead of 3 (startup windows and the rest for storage). what would be the best space for the start-up partition? is 17 enough, or too little? why/why not? what is a good program for repartitioning HDs? and do i have to delete all the partitions and reformat the entire HD in order to do this?

2) i wanna have 2 OS, Vista and XP. what's the best way of doing this? does this mean i have to have 1 partition for XP and the 2nd one for Vista? also, how does this work? does one OS loads on it's own or i have to choose which one i want to load every time i boot up my pc?


also, part of the reason why i'm doing this is because i can not run defrag for some reason. it always tells me that "some files could not be defragged" at about 5% or so.

p.s. i also have a 500gb WD that is SATA unlike my Seagate. would it be best to make it a bootable drive instead or it hardly makes any difference in speed. here are my specs:

2100+ (1.7 ghz) AMD Athlon XP, Socket A 462
Asus A7N8X Deluxe
2 HDDs, 200 Seagate, and 500 WD (SATA)
ATI Radeon 9500 pro video card
2 LG DVD Writers (1 old and 1 new)
100volt PSU forgot the name
3 Ghz RAM Corsair

what does that even mean? like to install vista and then have a program that opens xp inside of it? reason why i'm tripping on installing vista is cuz i heard most new games and programs are not supported (that, and the $200 price). not like i play anything new but hey, i dont wanna get a program and then have it not work.

also, is vista a lot faster then xp? considering my pc is a little outdated.