This is why you should grab a copy of Netlimiter, which afaik there is no free equivalent to for Windows. After you've downloaded, for example, 4GB of stuff, while you're waiting for your share ratio to reach 1:1 instead of hopping off the torrent as soon as the download completes, you want your uploads to go as quickly as possible so you're over-and-done-with-it. But capping your max speed means you won't be fighting having your cablemodems / DSL drop your packets, which makes the upload graph all yucky.
Remember, grabbing your content off a bit torrent and not staying on and seeding is like saying "I hate you for providing this stuff for me, g'bye!"