<font color='#000000'>Ah, so it's specifics you're wanting!
Time for my broken record number: grab the current and last month's issue of Consumer Reports. They have tested AV recievers and speakers therein. My only "firm" suggestion: get a reciever that is rated for 4 ohm speakers as well as 8 ohms. That signifies a decently robust power supply and amp circuit topology that's less likely to crap out during your office Unreal Tournament deathmatches*. Yamaha, Onkyo, and Panasonic all make good units. A "certain person" who frequents these boards seems especially bullish on Yamaha!
Read other's comments and suggestions here, and the staff reviews. A 10x20 conference room is about equvalent to a decent-size living room, though probably a bit "deader" acoustically. So look for people's living room system suggestions here!
I'm bullish on Cambridge Soundworks speakers, as many here know. Generally good to excellent stuff at all price points. Good warranty, excellent customer service. Check them out at hifi.com. Infinity, Polk Audio, PSB (getting pricey there, though) are a few other brands to consider.
Oh, and here's a tip about the center channel: the typical horizontal center channel is a poor choice for fidelity. Has to do with horizontal interference patterns between the drivers. There is a reason why high-fidelity speakers generally have their drivers arrayed vertically -- it puts the undesirable interference patterns where they will do the least harm. Unless you need to put the speaker on top of a TV, use a good small monitor speaker for the center instead. If you're using small monitors (not "mini cubes" or the like, but a good small monitor like the Cambridge Newton M-80) for the fronts (as you no doubt will), that means the three front speakers should be the same.
If you must get a "typical" sideways center channel speaker, try to stand it up on end.
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*You kids should play outside! Hacky sack, anyone?</font>