What do I buy?

You've got some good recommendations here already.  I'll add Aperion Audio.  Good quality, good value, good reviews, and great customer service.  Plus, they have very good center channel speakers (at least from 5C up) that are so important to home theater.  Also, you really need a sub for the complete home theater experience, and it will also significantly lower the power demands on your receiver.  Aperion has several HT speaker packages that are at or well below your price point including a sub.  Best of luck. 

Some good suggestions here.

I agree that MA offers a lot of bang for the buck and they can do double duty as HT/ Stereo speakers. The newest Silver series has a more benign impedance, and if your receiver truly meets its published specs, I wouldn't worry about the impedance dips. 

You should also add the Revel Concerta series to your list, a very different sounding speaker, but many like them.

In my opinion smooth surround performance is key to multichannel and /or home theater. I've had 5.1 systems with vertical left and right speakers horizontal center and dipole rears. After you get past the whiz bang of a new speakers the synergy of Home Theater systems simply sucks especially when listening to multichannel music. I've had both second hand and personal dissatisfying experience with Emo products.     

I've put together modest 5.1 and 7.1 surround systems for a few friends using economical $130. 88dB Pioneer SP-C22's a subwoofer and modest but modern Denon and Integra receivers. More recently using  $650. 91dB Triangle Voce's EZ and two Velodyne DD Plus 10" subs.

These are all center speakers placed as close to equal distance and ear level as possible. The 7.1 Pioneer/ Integra system in a spacious basement using very little room correction was a clinic on just how good surround can be when you have the space for matching speaker placement.