After a week of testing a friend's 20D with this lens, I decided to buy the 20D (body only). He'd just purchased a 30D and was looking to sell the 20D.
Took (so far) the best shots of my life so far with this setup.
After reading the reviews on this and other sites, decided to get the EF 50mm f/1.4 lens. Just bought it a few days ago (also second-hand), will write a review when I've tested it.