The toughest requirement for you is the dual HDMI output. Anything with that, will almost certainly have everything else. The old Yamaha RX-V867 was perfect, and inexpensive, but is almost impossible to find from a legit dealer now. The new 871 replaced it, but MSRP is $900. I'm not aware of anything from Denon/Onkyo/Marantz for less than that.
If you can go without the two HDMI outs, you would have your choice of a lot in the $300 street price range.
I see the advantages of getting a stereo/surround receiver as the ability to use that DAC instead of the Squeezebox's. For me, I'd probably go with an amp and hook the Squeezebox direct to that via RCA (primarily due to cost/spacial concerns), but I'm sure there are those who'd prefer the receiver over optical.
Speakers sound power hungry, I'd consider something like the Emotiva XPA2
@ $700 (300x2). The UPA2 is $289 and does 185x2 if that sounds too high.
As an aside I do own an Emotiva XPA3 and am very happy with it. I've direct connected it with an aux cable to an Ipod (in a pinch, for testing purposes) and it was good. Normally it's hooked up to a surround receiver though, so my tunes get played that way.