What's important in a budget HT in wall speaker??

I have decided to keep my 2 channel music and multichannel HT systems separate. I will be using 5 identical in walls for the HT, don't want to spend a huge amount. The room is about 4K cu feet. What are the important characteristics for these speakers?? My guess is that clear treble for voices/effects and a cost effective subwoofer (Hsu maybe) would be the way to go. I will likely use a mid range AVR, maybe get a cheapie amp down the road if I feel I need to move more air.

I have some Paradigm AMS 150s in the ceiling of my bathroom driven by a sonos integrated. for $150 off ebay, they sound pretty damn good. i was thinking of something from that line.

Any suggesstions??
I'd look the one's that let you aim the high frequency driver. I know they're out there I forgot what the brand.
isn't the key thing in HT dialog and dynamics? wouldn't that favor an efficient horn design like Klipsch?
He're my philosophy on this one. The "budget in wall" segment is very price competitive. Although all owners will like their own speaker you really don't know which $500 speaker you are going to like best unless you hear them. Given that, I would just assume the top 3-4 selling speakers in the segment are all pretty good, and look for the best deal you can get on any one of these and take your chances. Like you, I ended up with a pair of very nice paradigm in walls for my surround channels on ebay this way. So just draw up a shortlist of 3-4 and look for a killer deal.