These are reasonably priced lenses I've used on a crop and have been satisfied with.
Tamron 28-75mm f/2.8 To quote Roger Cicala (LensRentals)..."The Tammy is the best lens nobody knows about, and possibly the best bang-for-the-buck of any camera lens— period."
I very much agree and have used it on 40D and 60D, this would be my first recommendation.
Tokina 11-16/2.8 I have the older version, it spends a lot of time on my cameras. Aperture ring is easily de-clicked for video if that's your fancy. While quite good, the MkII is a bit better.
A must-have is the 50/1.8 Cheap and functional. Just get it. With some Kenko closeup rings you'll have macro at a good price point.
RokSamBow 8mm fisheye Cheap, fairly good. Used often enough that I'm glad I have it but not so often that I'm willing to pay quite a bit more for a 'better' one. Along those lines, the RokSamBow MF primes are optically pretty good. AF and IS are important for some types of photography; not so critical for a hobbyist.
Sigma 70-200/2.8 APO Several flavors exist, I bought mine used about 9 years ago and still use it quite a bit.
On the tele end -
300/4L non-IS Older, discontinued, very good wide open, amazing at f/4.5. IMO Canon's best 'affordable' long lens. They show up on FredMiranda once in a while, but not often. Folks seem to just keep them, I know I will.
Sigma 400/5.6APO Macro - older, discontinued. AF will work but aperture control will NOT with your 7D. Known to develop a fungus problem if not well cared for. I only include it because it is surprisingly sharp wide open, the macro ability is quite good and it is often available for well under $200. I paid $120 and another $140 for cleaning. It's big and heavy, but much better than the 70-200 with 2X extender.
EF 28-135IS Kit lens with 40D. It works, IS is nice, but I've never been particularly happy with it. Stiff zoom and beyond soft wide open.
If you haven't done so already, head over to LensRentals and read 'Roger's take' on the lenses you're considering. He seems to call it the way he sees it, no fanboy BS. That was my basis for first renting then buying the Tamron 28-75.