I would recommend the pro 12 for just about any application. Very efficient, sounds great, but you do need a sub (very little bass response). They even sound great with an electric guitar.
If you are tight on cash, I can recomend this speaker
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-032. To save even more you can also skip the crossover, run the woofer full range and just use a capacitor on the horn. You might need to add a resistor to tame the horn down a bit though.
DanK