Fonts that you have on your Pc are always the best. just play with reducing the space between the letters, etc. When you cant find a good way to do text, just dont do it. The sig will look x100 better. Practice makes it perfect. =)
I know im new here but listen... you cant ask what is the best font for a sig becuase everyone likes differnt fonts. I personal think a handwriting font looks cool as a personal sig on all your work. but realy, make your own. (not trying to sound mean) im not great "YET" at photoshop but a fun thing to do is just use the "wind" tool and then rotate the pic so you get it sharp on each side. ill show you an example in a sec. one i find out how to post it lol.
you cant realy ask what the best font. everyone has there own fav and if you ask me, just go with what you like. OR make your own. i mean in literaly 1 minite i can make a flaming font and im not that great yet. so just play with it.