Probably the most popular reciever is the Denon 3808 ($1200 US) most other Denon models will also power a 4 ohm load reliably.
The new Onkyos like the 805,806 875,876 etc should handle a 4 ohm load. Also the Sherwood Newcastle recievers are recomended. Other factor to take in to acccount are the size of your room and the volume level you listen at, the larger the room and louder the volume requires more amp power.

Dave