woah, raid 0 = half mean time till failure. it's awesome till it breaks and you lose everything. if you're going that route, i'd really suggest hardware raid 5 for some kind of safety net... unless you keep good backups, which almost no one does.
and yeah, ghost is truly amazing
the best hard drive deals are ALWAYS rebates at compusa/staples/best buy etc, when available. otherwise, you can get a 300gb for 90$ (newegg.com) non-rebate (which is the best price/size right now). once you have the space, you'll figure out how to use it
. seagate is a little slower, but they use less moving parts and fail less often. hitachi and samsung have low fail rates too.