The 28-135 isn't a "bad" lens, but neither is it particularly great. When I had one it was decently sharp from 28 to about 100mm or so - kinda crappy beyond. Also the IS is from the 1st generation (late '90s) and doesn't perform nearly as well as that in more modern lenses. The current kit lenses 18-55IS and 55-250IS are both at least as sharp, cheaper and have better IS than the 28-135.
My recommendation for a low cost kit for the 7D would be:
50/1.8 or 50/1.8 or 85/1.8 depending on budget and preference.
If your interest deepens and budget expands you may find that the 10-22 and 17-55IS zoom lenses also work very well with the 7D. All the L's and primes work well too, but they generally cost a lot more and may be more specialized.