40D awesome. 50D... 50% more pixels with the same tech = very noisy, IQ is better on the 40D but better spec in the 50 (screen res, AFMA etc). The 17-85mm probably the worst lens I have ever had. Kept it for a long time because I was a student and couldn't afford the 17-55mm. Its poor everywhere it counts. Bought the 17-55mm after uni its a huge upgrade. Then 24-105mm on FF is comparable.