I use the EF-S 17-85mm f/4-5.6 IS USM as my all around (I have a cropped sensor XT, so the range is ~ 28 to 135mm @ 35mm equiv). Not too expensive and has IS. IF I had the bucks to spend, I would consider either the EF 24-105mm f/4L IS USM or the EF 17-40mm f/4L USM if you don't need the range.