Sonar Production has more instruments than any other...I think it comes in at a whopping 14 gigs..but it is expensive..it will do everything you need..for good
Reaper is $60, it takes VSTs so adding instruments and effects to it is no problem..it is also minus the "flab" like video production tools etc..
cubase, protools, and logic are much the same as sonar..give or take a few instruments..
Ableton Live is another contender..great for performing live and as well as recording pretty much the same as the others.. it also has an separate recording area that breaks everything into loops that you can remix on the fly
Reaper, Sonar, and Ableton all have fully functioning downloadable demos that you have about a month to muck about with, I don't know about the rest..see which one you get along with best??
but dont skip that reading...its a must