Help -- Which Router ... ???

We need to get a new router ... When I get my new Mac Pro 3.33GHz (soon!) the modem (Clearwire) will be hard-wired to my Mac Pro.

My youngest son's computer (HP Slimline) will be hard-wired to the router. My oldest son's computer (HP Pavillion Elite) will connect wireless. Our laptops (iBook G4 and PowerBook G4), and our roommate's laptop (MacBook Pro) will all connect wireless.

I've was looking at the DGL-4500, but recently have learned that it will not allow 2.4/5 GHz connection simultaneously. I've also been looking at the DIR-655 Xtreme and the DIR-825.

I know almost nothing about routers, and have no clue what I should be looking for ....

I've been using my D-Links 524 router for almost six years, which has been working flawlessly! But we are having too many problems with our connection signal, lagging, getting disconnected and having to reboot the modem/router too often. And now we have so many computers to connect online.

Both of my boys are doing online gaming, and so they need solid, stable connections.

I don't mind paying $200 or more for a high-end router. Also, I want to have free tech support for at least a couple years (like I did with my old D-Links 524).

Suggestions ....