To use live with my band. Can anyone name me a few different programs? Preferably for mac?

weirdly enough i was just looking for a sampler. What ive been looking at is the sampletank 2.5 xl by IK multimedia. a big plus of it is that it can run with just 512MB of ram, recommended for a gig though. The soudns on it seem pretty good, good enough for anything id be doing. the xl version goes for around 300$ pretty good deal. http://www.ikmultimedia.com/sampletank/features/
id suggest listening to some of the audio. the bass and guitars arent very good but all the synths,orchestrals, and choirs sound really good, i just need to find out if they can do good brass orchestrations as those are really sick when implemented into metal songs.