If you've never seen a match from 2006 then I suggest mulling through a few old ones on the Blue Alliance website. This is a link to Einstein 2 to give you a general idea of some of the best from that year (this is also my favorite FIRST match from any year I competed so I love to show it to people):
http://www.thebluealliance.com/match/2006cmp_f1m2
There were a handful of catapults but most teams used a flywheel or pair of rollers to shoot. 25 I believe attached arms onto a rotating wheel to "fling" balls in a sort of hybrid.
As already mentioned precision takes on a whole new importance not needed in 2006. Hitting an 18" target on a downward trajectory is significantly more difficult than hitting a 30" target at an upward angle in my opinion. I know my team's flywheel shooter could have enough variability in the delivery position that I wouldn't rely on it this year; I'm leaning more towards a pair of rollers/wheels that can control both sides of the ball for better precision this time, or something that throws the ball instead.