I too recommend the Sennheiser MKE40. Very clear, detailed and warm/pleasant sound. The number one complaint with PA recording for me is clarity of vocals, and these mics work great. *If* you need a bit of bass, just bring that up with a bit of EQ. But most venues overdo the bass anyway, so I don't mind a bit of roll off. If I had to recommend a cardioid, these would be it. The Church CA-11 are good too, and about half the price, but for $250 I would get the Sennheiser. However, make sure you get these modded for loud shows. Chris Church can help you with this (probably).
Before going to cardioids, though, I would give Omnis a chance. For $150 the Church CAFS are very good. If you want a really good sounding omni, try the Countryman B3.
Clips of all above (except for CAFS) are available at
http://soundmann.com.
Richard