My 7D body has been shipped and should be delivered tomorrow, hopefully. So for now it will be the 18-55 kit lens I have. But since my full frame camera purchase is years away, I'm going to take the suggestions/advice of sticking to EF-S for the near future.
I'm still flip-flopping between the Canon EF-S 17-55 and the EF-S 15-85 as my "walkabout" lens. I know the 17-55 is better for low light and the 15-85 has more range.
Either way I hope to pair the "walkabout" with an ultrawide, either the Canon 10-22 or the Sigma 10-20.
My budget is limited so, I may only be able to get one lens for now and maybe another next year, in that case I'm leaning towards the Canon 15-85.
Thanks for all the input.
Sounds good. I'm very happy with my 15-85mm as my walk around - particularly because of it's great range, very good IQ and useability. I have the Sigma 10-20mm as my 'ultrawide', and 10mm is significantly wider than 15mm (though 15mm is nice to have as the wide end of a walk-around).
The Sigma 8-16mm is also a very nice lens, as are the Canon 10-22 and Tokina 11-16mm. Actually in the ultra-wide selection these days, people are really spoilt for choice! When I bought my ultra wide, there were much fewer options, and I went with the Sigma, it's served me well.
As for 'low light' - when I want fast glass, I need primes. That's why I didn't go the 17-55mm - it was too much of a 'half way house' for me.... not quite wide enough range for my walk around needs, and certainly the f/2.8 helps in low light... but a f/1.4 to f/2 is usually what I call 'large aperture' glass.
All the best