The Yongnuo works as good as the ST-E2 only costs half as much to buyWell, I'd go for the canon ST-E2 first. Then Pocket Wizards, but the canon is going to be cheaper than a trigger and receiver for the PW's.
I forgot... Yongnuo makes a knock off of the ST-E2. I have no clue how good it is, but you might peruse www.strobist.com to see if Hobby has anything to say about it. He loves the yon