Lighting for a 4-piece rock band

If it were me, I'd go with 8 pars on each stand, 16 in total, that would give you a small concert type of look. and then get some other effects lights such as a couple Roto Pods, one on either side of the drummer on the floor pointing up and out into the audience. They are fairly inexpensive and a very nice effect especially with fog. There are other lights that you could use for a backdrop effect such as the H2O that looks like rippling water that changes colors, or the new one that ADJ has out call Fire Burst that looks like flames dancing on the wall. It doesn't have a duty cycle and can be run all night if you like.

another cool effect is a Vertigo on the floor behind the frummer, pointing up at his back kind of...also, having a full truss behind your band, with 16 or so par cans(or more) and like DOGG said, Roto Pods