many people think partial seeding is a good way to improve your ratio. let me tell you why i think this is wrong.
let's pretend you grab one rar of a popular xvid and seed it. let's also pretend the torrent gets 20 snatches after you start to seed:
20 x 14mb = 280mb upload - 14mb = 266mb buffer, file ratio 20.0
let's now pretend you donwload the whole movie.
20 x 700mb = 14gb upload - 700mb = 13,3gb buffer, file ratio 20.0
the ratio improvement is exactly the same. it doesn't matter wether you grab only a part of the torrent or the whole thing. the key factor is the total number of snatches you get.
when you download the whole movie you can:
a.) watch it (which is the purpose of downloading movies in the first place)
b.) get a much higher buffer!
please don't tell me that you save harddisk space. if you can't afford 700mb saved to your hd, get a bigger one (they're cheap) or delete some files.
the only case where partial downloading makes sense is, if there's a pack and you only want a portion of the content.