Hypersmurf
Moderatarrrrh...
What's wrong with empowering a summon spell? It has no effect on the creature summoned, but with the higher level spells you can get a variable number of creatures from a lower list.
You'll notice my "No" was in reply to the question "when summoning only a single monster".
Yes, an Empowered SM III can summon half again as many creatures from the SM I list.
-Hyp.