I would recommend not setting it above 75% of your total upload speed (you can ask your isp if you dont know). You can set it lower than that, but remember always try to share to at least a ratio of 1.5 (you upload more than you download.)

Leaching (downloading and then removing the torrent without letting it upload) is just plain wrong. Many folks whine about having slow download speeds on a torrent, yet as soon as it finishes they remove the file. That means anyone else that’s still downloading the file can’t get the speed boost that your computer would have offered.

20Kb upload? Both for dialup or 10Mbit optical line? Seriously?

If people think that integrated calculator integrated in utorrent is somehow wrong they can use any external one like http://infinite-source.de/az/az-calc.html