UltraHLE/SuprHLE is quite good, but has a low compatibility. Try pj64, which is the best for most games. It requires a good pc, while UltraHLE needs a low-end one, but I'm sure your pc can handle it pretty well. Try all emus if you want to. The best emu really depends on which game you're going to play. Check compat lists to see which emu run the game you wanna play.
Sephiroth: for my personal experience... I tryed UltraHLE with my old k6-3 500 and my old i740 with glidea wrapper and it works fiine with games like mario64, starfox and zelda, but don't expect more than that