Like others have said, Volcano is a very good, very unique ride that is definitely a must ride at the park. In my opinion, it is the second best coaster there, and I actually preferred it to Intimidator 305 (note: I only rode I305 with the trim brake). Also, you definitely want to ride early. When I visited, I did a quick run on I305 before going to Volcano, and by the time I got there the line was already 20 minutes. By the time I got off, it was over a half hour, and this was a day where almost everything was in the 15-20 minute range (only other ride I waited more than 20 minutes for was Avalanche). I don't know the exact numbers, but I'm guessing Volcano with two trains has about the same capacity as I305 or Dominator with one train.
Top 5 Steel: Bizarro (SFNE), Tatsu, Maverick, Kingda Ka, Top Thrill Dragster
Top 5 Wood: El Toro, Voyage, Boulder Dash, Thunderhead, Ravine Flyer II
Top 3 Parks: Busch Gardens Williamsburg, Holiday World, Cedar Point
TPR Trips: IntimidaTour 2010, North East Trip 2011, LeviaTHON 2012