I just picked up a used leupy mark 4 cqt. Although it mounts a little high on rifles (seems to be made for the AR) Its still usable.
http://www.leupold.com/tactical/products/scopes/
Optics are awesome, reticle is simple and its illuminated. All in all, if I didnt have an AR to put it on, Id happily use it on a rifle or shotgun and figure a way to get the comb higher.
Other than that, Bushnells in the 3200 or 4200 variety are awesome choices. I know that a 3x9x40 isnt as awe inspiring as a 6x18 or something like that, but they are popular because they are practical. Heres a good choice-
http://www.bushnell.com/general/riflescopes_elite3200_32-2732m.cfm
