Usually 5-30 kb/s for the types of files I download, which are generally around a gig, give or take. However, I often get short bursts of 50+ kb/s and on smaller, very popular files (such as game demos over at filerush.com) its not uncommon to download above 100kb/s and sometimes even several hundred.
For example, a 1.2 gig file (which shall not be named) recently finished, averaging about 10 kb/s I'de say. But at the same time, the Silent Hill 4 demo from Filerush.com averaged about 400 kb/s.
note: I'm behind a firewall, so, uh, take that into account.