I'll throw in my vote for VCA's too. VCA's are very nice and different than using a bus.
This is because if you turn down the volume of a bus, all of the effects routed out of the sends on those individual tracks that route to the bus will lose their relationship to the dry signal.
For example. Let's say you have all your drum tracks routed to your drum bus. Your snare track probably has a different amount of reverb on it then your Kick and etc., thus you have the reverb sends on the individual tracks, not on the bus. Well, if you turn your bus all the way down, notice you still hear all the reverb from the auxillary sends of the individual drum tracks. So, if you turn up the volume on the drum bus, the drums will have less reverb. If you turn the volume down on the drum bus, it will have more reverb. This is usually the exact opposite of what you really want.
A VCA is really nice because you control the actual volume of all of the individual tracks with one fader. Because of this, the auxillary sends maintain their relationship with the dry output.
You can use groups, but that can become very messy when you are automating volume changes on 12 or so drum tracks. Plus, there will be times that you might just want the snare louder, or the toms louder and etc. This leads to really messy automation that a VCA can definitely make easier and cleaner.