here is a possible system for you:
JTR Orbit Shifter Pro
Amp for the Orbit Shifter
Behringer Eurolive speakers
That is a system with a heavy emphasis on bass capability. The speakers are fine, very good for the price, and should do the trick for large parties and also small auditoriums, and the sub is a monster and will be felt for sure. If you really want to do a good job,
read this carefully! Since that book is available online, you have no excuse for screwing up. Do your homework on this, and you will be throwing kick ass parties.
One more thing, protect your ears if you have to work next to this system while its playing. It
will cause hearing damage otherwise. Use 30+dB rollup type ear plugs.