I think the 85/1.8 is a one of the best values in the Canon lineup in terms of IQ/dollar. It's excellent for tight portraits on APS-C, good for indoor sports on both formats.
I bought this lens as part of my 'starter kit' - T1i/500D, 17-55/2.8 IS, 85/1.8, and 430EX II. I eventually upgraded to the 85L II, but liked the 85mm FL on APS-C so well that after getting a 5DII, I also got the 135/2L.
Here's a shot with the 85/1.8. There is some longitudinal CA (purple/green fringing) evident in the sunlit hair. The OOF background is actually a dirt path - the thin DoF is great for outdoor portraits!
Rebel T1i, EF 85mm f/1.8, 1/2000 s, f/1.8, ISO 100