C.J.
for the first sippy cup, I always look for one that somewhat emulates a bottle. meaning it is a soft spout and child gets liquid by tilting and sucking the spout, not a straw based.
Eventually we moved to a straw, but those were my only criteria for the first cups.
I did see an excellent selection on the Daily Candy kids email a few months ago (they archive them on their site dailycandy.com) and it was a great listing of sippy cups and converting regular cups to sippy cups,e tc. You might want to take a gander to see if you like any there:)