Usually set my upload limit to 45 kb/sec, and 20 when gaming, out of my total of 70 kb upload, reason is beacause i don't want my parents to experience slow internet, i'm only one out of 4 pc's on this single 5 mb connection...
As for speed, try joining a private tracker, you may need to keep your share high (usually minimal 0.5, 1.05 for some extra privelges) but that can be archieved easely by uploading at night...
On the tracker in question i usually get full speed 500kb/sec and my mate wich also is registred downloads a 1.2 megabytes/sec from it, the torrents are really ultra fast.