I primarily use a Canon 50D body and a Tamron 18-270 telephoto lens, as my "walking around" lens. Excellent wide angle and telephoto combined into one lens, and very lightweight. This lens has been a workhorse for me but it's starting to show some signs of wear. The focusing isn't as crisp as it once was and I can't seem to correct it using micro adjustments built into the camera.
I've had it repaired, and while they replaced some parts, it's never been the same. I'm not looking for an excuse to buy a new lens in this price range. When I'm out and about, I prefer not to have to carry a whole gadget bag of lenses to fit different situations. This 18 - 270 fit just about everything I needed.
Just curious...what's your "walking around" lens?