1) What source are you planning on driving the sound board from? Arcade video game, XBox, PS2, PS3, ....
2) Is this source stereo or mono?
3) What type of speakers are you planning on driving? 6", 8", 10", 4ohm, 8ohm.
4) If stereo are you planning to use woofers & tweeters, single cone, subwoofer?
5) Multiple speakers (subwoffer, woofer & tweeter) are you planning on a separate crossover network or do you want the amp to supply those?
6) Do you want an off the shelf or are you planning on building custom from components?
There are a lot of options out there from a $5 Radio Shack special to a $2000 Nakamichi pre amp & amp stack. Details help nail down what you are trying to do.
ken