I have used both FF and APS-C DSLRs for several years. I currently own a Canon 7D and Canon 350D... and have owned both EF and EF-S lenses since I got into DSLRs in 2005.
My current mainstay of "go-to-body" and lens combination is the Canon 7D with Canon 15-85mm. It's vastly superior than the 17-40 in IQ sharpness, focal length range at both wide and tele-end, usability, IS - and at least on-par USM. The only advantage of the 17-40 is a somewhat better build quality (also incorporating improved weather sealing).
When I was considering what lens to use as my walkaround for my 7D, I had owned a good copy of the EF 28-135mm - but it is not as good as the EF-S 15-85mm even at equivalent focal lengths. I have an EF-S 18-55mm (but a non IS version) so that's "ok" the IS version of the kit lens is better The newer EF-S 18-135mm STM is quite good (better than the non STM one).
Macro-wise, I went with the Canon EF 100mm f/2.8 USM, over above any 3rd party (mainly to do with AF and IQ). I chose the EF 100mm over the EF-S 60mm, really only due to preferring a longer working focal length when doing macro photography. I am glad I did... there was a small consideration that if can also use this lens on a FF.
I own an EF 70-300mm USM IS L - which is a truly great lens, and as photozone points out - is superior on a crop body (in terms of using the sweet spot / centre of the lens) - and gaining the 'crop factor' advantage, that is presents a 480mm equivalent image on a APS-C body. But even if this 70-300mm L would have been an EF-S... I still would have bought it!
Finally in UWA land, I own a Sigma 10-20mm HSM EX... which is a great lens. When I was considering UWAs, there was much less choice then than there is now. I went with a new Sigma 10-20 based on a much better price than I could get a new EF-S Canon 10-22mm USM for. My Sigma gives me sharp corner to corner images at the equivalent of 16mm in 35mm format.
Lens wise, I say buy what you can budget / ie what is affordable to you - and what you will use often now. That's my 2cents worth.
+1 on the Sigma 10-20 on my 7D. I don't use it often, but am always very pleasantly surprised when I see the quality of the images. My other glass is Canon L, and to me, the Sigma is just as sharp.