Being in the military, can you get deals in the PX? Or are those days over?
If you go with the major brands like Yamaha, Onkyo, Denon, Panasonic, Sony and so on you'll be pretty safe. One good thing about the market today is that nearly all the gear from the majors is at least competent (I hear some throat-clearing in the background! Hey, I said NEARLY.).
I'll give my usual advice to newbies without oil-sheikh incomes: find a copy of the November 2003 Consumer Reports. That is the last time they did tests of receivers. They might also have ratings on their Website,
www.ConsumerReports.org. CU is the only publication I know of doing regular objective testing of mass-market non-exotic HT and audio gear. If my wife wasn't so ruthlessly efficient at throwing out old mags, I could name you their top picks but..
Look for a unit that is rated for power into 4 ohms as well as 8 ohms; it indicates that the unit has a more robust power supply for the amps which is a good quality feature to have even if you have 8 ohm (most speakers are) speakers. For technical reasons the power rating for 4 ohms will not be double that for 8 ohms; that's normal.
Don't get hung up unduly on the watts, either. Unless you have a large listening room in your mansion or very inefficient speakers (neither of which applies in your case

) any decent receiver will have enough power for your needs. Your subwoofer has its own amplifier built in and it's the bass that takes the most power.
Don't sweat THX certification; it costs more and is not a must-have. $200-$300 will get you a good Dolby and DTS equipped unit. For your speakers you need a "5.1" channel receiver. If you get a "7.1" unit you can add two more rear speakers in the future if you wish.
Enjoy. This stuff is simpler that a lot of us make it seem.