I have a 7D which I use with 17-55 f2.8 and 70-200L f4. I upgraded from a 550D. There is no difference in image quality, but once you move up from the kit lens, it feels much better to hold (IMHO) and the AF is really good. The user interface is better, which helps. I’m pleased with the upgrade, but if your sticking with the kit lens, personally, I wouldn’t bother over a 550D/600D. Micro focus adjust has also been worthwhile.
I’m not sure i’d partner it with the 18-135mm, but each to their own. Digital Rev have a decent rep, but I used HDEW and they were cheaper at the time and had good service.