My advice is don't get too elaborate right now. Friends are going to get drunk at parties and start playing with the volume knob. Unless the room is really huge I'd go with a set of Infinity Primus speakers... 3x P163 for mains and center and 2x P153 as surrounds. Lay one of the P163s on it's side and rotate the tweeter 90 degrees and you have a center.
Add a nice factory re-certified but far more capable Onkyo TX-NR708 , and the best $200 subwoofer that you can find. I'm not an expert on $200 subs so I'll leave that to those in the subwoofer forum that know them best. If the room big you can always add a second sub later. I do have some experience buying factory re-certified Onkyos from A4L and both times the transaction and product were flawless.
That's a complete 5.1 system for $1050 including ~$200 for the sub.

Add a nice factory re-certified but far more capable Onkyo TX-NR708 , and the best $200 subwoofer that you can find. I'm not an expert on $200 subs so I'll leave that to those in the subwoofer forum that know them best. If the room big you can always add a second sub later. I do have some experience buying factory re-certified Onkyos from A4L and both times the transaction and product were flawless.
That's a complete 5.1 system for $1050 including ~$200 for the sub.