eventhough i havent really gotten the whole text thing down yet, what i keep hearing is "keep it simple". i downloaded something like 250 fonts ranging from ac/dc fonts to zimbabwe script and everything inbetween. all this did is make the choice of font the hardest and most time consuming part of the sig/artwork. keeping it simple helps. also, instead of choosing "which" font, try thinking about what you want to do with the font. maybe multiple colors, maybe intermixing words, wordplay, working it into the art, etc. look at this link and you'll see what im talking about.
http://www.gfxvoid.com/forums/showthread.php?t=6450
the sig isnt great but what he did with the font was very basic but very impactful, imo of course.