one thing I beleive is important is that the center's sound matches the mains. For this reason, I would stick with the same brand/line for these 3 speakers. Also, I have a pretty high end Yamaha receiever, and I can tell you that although there are some very good 4 ohm speakers out there that you would be better off getting 8 ohm speakers if your going to drive them with a receiver. I love dynaudio audience speakers but frankly they just don't mate that well to receivers in opinion because of this.
There are a ton of speakers out there that would be a good match for the system it appears your trying to build. first you need to decide if you want direct or dipole speakers. For dipole I would chose Definitive Tech, but I prefer direct speakers so I'd recommend Paradigm. They are great for modest priced home theater, and thier studio line is actually pretty good with music too. They are not really considered high end by alot of people on this board, but they do offer a good price to performance ratio. I have a feeling they will offer the sound your looking for.
There are a ton of speakers out there that would be a good match for the system it appears your trying to build. first you need to decide if you want direct or dipole speakers. For dipole I would chose Definitive Tech, but I prefer direct speakers so I'd recommend Paradigm. They are great for modest priced home theater, and thier studio line is actually pretty good with music too. They are not really considered high end by alot of people on this board, but they do offer a good price to performance ratio. I have a feeling they will offer the sound your looking for.