If you look for your first macro lens to use with Canon 7D,  the best bet is to get Canon EF 100mm f/2.8 USM.

Canon EF 100mm f/2.8 USM gives a focusing equivalence of 160mm in a 35mm camera. The lens has a fast internal focus ring with ultra sound motor (USM). The minimal focus distance is 1 foot resulting a magnification ratio of 1:1. Canon 100mm f/2.8 USM has a filter size of 58 mm and the building quality is very good. Canon 100mm f/2.8 macro has great image quality with very little chromatic aberrations, distortions and vignetting.

Although the new Canon EF 100mm f/2.8 IS USM has hybrid image stabilization which can compensate both angular and shift camera shake. Some review indicated that the IS was not particular effective at macro shooting.

Some people might like Canon EF-S 60 mm f/2.8 USM. But this lens was only $90 cheaper than Canon 100mm f/2.8 macro and has a shorter working distance. Canon EF-S 60mm f/2.8 can only work on APS-C digital SLRs. I think Canan 100 mm macro is a better choice.

If you don’t mind third party lens, Sigma AF 105 f/2.8 EX DG macro and Tamron AF 90mm f/2.8 macro are good choices too.