Virtually any wine yeast. Any mead yeast. You can use ale yeast for a lower ABV mead; I suppose you could even use a lager yeast to make low ABV mead.
In the immortal words of Jack Keller: "Choose a yeast like you would choose a tool."
He has a handy list of wine yeast strains here: http://winemaking.jackkeller.net/strains.asp
If you can tell us what you want to make, and which yeast you have available, we might be able to give you more specifics. Wine yeast are commonly used, with Lalvin 71B and K1V-1116 being two of the most frequently selected ones.