I would highly reccomend the canon, the range of lens's are fantastic!! I live in the uk so we have the 400D which I think is the xti in america. The image quality is fantastic, its light and like the sony and olympus it has a dust removal system. One draw back it doesnt come with IS as standard like the sony, meaning you normally have to buy the L series lens's to achieve this. Fortunatly the noise you get from the ISO is very low indeed! Meaning shutter shake will be cut to a minimum. Also the software you get is extremley good!
If your not keen on canon, you can look at Nikon which also has a good range, the nikon's are also a little more rugged, but the lens range isnt quite as good as canon's
Photography has been a long time hobby of mine. I am venturing out to buy my first SLR camera and I need advice! I have been researching and I still can't make up my mind. Originally I had my heart set on the Olympus EVOLT E-500...my point and shoot camera is an Olympus and I think it does an awesome job. Then I looked at the Sony Alpha and was really impressed with the 10 megapixels. Then a friend recommended the Canon XTi...I got to reading reviews on it and also added the Canon XT to my list. I really appreciate any advice you can give!