First, I recommend staying at 5.1. No need to pay for two extra speakers that will rarely be used - in that price range. Buy a NICE center and 12" sub. I am a snob - no 10" sub will match an equivalent quality 12".
I have a 5.1 in the bedroom. Waste of money.
I have a 7.1 in the LR. Nice, but rarely used to full effect. $800+ in those speakers, easy, maybe more.
Onkyo AVRs in both locations, hundreds of dollars each.
IF there is any chance of UHD TV or even 3D, go for the latest HDMI, 1.4 or 2.0. I think in that price range, trading off wattage is in the cards. If there is no reasonable chance of UHD or 3D, save bucks with an HDMI 1.3 AVR and put the difference into speakers, especially the center. No need to match my Klipschorns, but there are plenty of good speakers in that range.
I submit $1500 would GREATLY increase quality.