I am not all that familiar with projectors, but I know there are some good projector options at the $1000 price point, and you should be able to find a screen with the rest. I would try and look for an acoustically transparent screen, this will let you put the speakers behind it, and go with 3 identical speakers, providing the most ideal front sound stage.
So lets assume you are able to get an AT screen, here is what I would recommend:
3 Klipsch RB-81 II for your front L/R and center. These are a much better choice than the RF-62 towers because you get a bigger woofer leading to better dynamics and output. Horizontal centers are compromises in sound quality for the sake of convenience, so with an AT screen you can avoid this compromise.
I would then grab 2 RS-52 II surrounds, depending on your room layout. Reference the THX website for proper placement of bipole surrounds.
This would be $2000 for all 5 speakers, but you could drop down to the RS-42 II if you didn't want to spend as much.
Since you have a medium size room, I would look at a pair of Rythmik LV12R subwoofers, these are fantastic, very accurate, and have great output. Use the last bit of cash for a receiver, something like the Marantz SR5008 would be a good choice and it has preouts if that is something you want, otherwise the Denon X2000 is a good choice. I would use www.accessories4less.com
to get one refurbished and save some money. With the high sensitivity of Klipsch, these receivers will make the speakers louder than you can stand to listen to them, and they both offer better room correction software than Pioneer and Yamaha.