congrats! i just picked mine up last night too.
so here's a brief list of recent Intel Mac apps that come to mind:
-Automat - freeware synth
-Renoise - tracker application
-Live - ...obviously
-iDrum - reason like Redrum
-Expert Sleepers - various looping, sample oriented plugs. some are free and some haven't been ported yet
-Audio Damage - plug-ins. these are great...not free but really worth the little bit of money they cost
-Crystal - freeware synth
-Reason - just announced yesterday
-StylusRMX - fancy drum/loop plugin
-Arturia Prophet V - plug
-Wave Editor / Sample Manager - Excellet Audio editor and sample managing apps...expensive but really nice.
others have been announced and more on the way everyday. i'm sure i missed quite a few here. i was just looking yesterday at the same thing. i think with Live + Automat + Crystal + few plugs one would have a simple but really powerful rig.
i kinda like the limited palette that exist for early adopters right now. it will help keep me focused on just a few...which was a direction i've been heading into for a while anyway.
Live + Automat
good luck and enjoy!!!