IMO, SM57 lack both the reach and detail needed to be effective overheads. One of the best budget condensers I've used is the Perception series from AKG. I own a Perception 200, and have had good results with it on acoustic guitar and as a single drum overhead on a small kit.
+1
You really need a condenser mic for use as an overhead on a drum kit. I use a pair of Behringer C2s and they sound absolutely fantastic. Invalid Link Removed