It's according to what kind of sig you're planning to make, just experiment a bit, use bevel and emboss and some outer glow and so on, you know, just experiment a bit and you should find a good look for your sig.
Giving the text a stroke that contrasts its fill always worked for me. Apart from that, creating a duplicate and displacing it by a few pixels and tuning down its alpha and placing it behind the original text always looked nice.
