High Powered Wireless Network for Audio

I have ATT DSL and run nine different wireless devices without issue. I have a Linksys "N" router located in one corner of my 2800 sq ft house, but I am fortunate not to have any immediate neighbors (I can detect two other networks, but they are very weak). I can listen to my squeezeboxes and/or watch netflix movies through a PS3 and surf the net at the same time, etc. I honestly can't remember the last time I had "drop out" while listening to my Squeezebox. As Vett93 point out. the key to good wireless service seems to start with a relatively "clean" environment, followed by proper configuration of your router, firewalls, etc. If you're getting a lot of external interference, you probably need to look at a wired solution.

Your router may be just getting tired. I had an access point that seemed to put out less signal as it aged. I went with 2 access points because I have a lot of foil faced insulation in my house as well as duct work which I think created shields. The line of sight from my den to my patio is completely blocked by my house causing occasional dropouts. Placing the router in the center of the house was also not a great option for me.
Whatever router you choose, I would recommend the gigabit ethernet variety (10/100/1000) as opposed to an N router that only does 10/100. Linksys makes 2 types of dual band models, one where you choose either high or low band and use only one band at a time, and another that puts out 2 bands at the same time. BTW-the bands have nothing to with channels. You would still choose the channel for each band with the less interference.