What room conditions did you view the Benq in?
If a projector's settings are not setup correctly (contrast, brightness, gamma, or color), then it can look pretty bad. Also if the room isn't light controlled, all PJ's will look semi-bad in some scenes. The Benq has the same or slightly better blacks as the Epson 8350 does even when the Epson's IRIS closes down, in a way the Benq's blacks are slightly richer, but they are similar to the Epson. The Benq is much brighter though, so if you saw it on a normal screen without an ND filter near the Epson, the Epson is going to look like it has better blacks even though it doesn't.
That said, the blacks aren't going to be great with any of these sub-$1500 DLP's, the best blacks for under $1,500 is the JVC HD-250 B-Stock from [email protected]
(if he has any in stock). Other than JVC's, there aren't going to be great blacks.
I would up the budget by $300 to $400 and get the JVC HD-250 B-Stock if you can find one. The issue with the JVC for you though will be lag-time. Better blacks and better gaming performance does not exist in this price category, to get that, you would need to buy a Sony hw50es, or maybe an Epson 5020 (though the Epson as more lag than the sony, it has a bit less than a JVC). The JVC will work good for almost all single player games, but if you are going to put a bunch of gaming hours on lamps, maybe stick with the Benq w1070... You will need to compromise something, if it were me, I'd get the JVC and play most multiplayer games on the TV or something.
As far as receivers, I'm no expert on the audio topics by any stretch, but as much as I love Sony Bluray players, avoid Sony receivers. I also think Pioneers are overrated (I own one), but maybe that has changed.
I like Denon or Harman Kardon receivers personally, though most receivers are ok (Onkyo, Pioneer, whatever). Denon 5.1 receivers aren't that expensive anymore (even new), the 7.1's are a bit pricier. I would base your receiver purchase more on what features you want/desire (like ipod integration or what not, though there are ways around that regardless of integration features). My advice then, just avoid Sony, Sherwood, or any of the super low-cost receivers, the others are usually similar.