I had this problem… whenever I would walk into my house with my Nexus One, and it connected to the internet, my router would slowly die. I would have to unplug the router from the power and plug it in again to fix it. I think I’ve found the solution, at least for my DI-624 wireless – N router.
It turns out that there must be some problem with the Nexus One handling TKIP encryption, or at least with the way the D-Link DI-624 is sending it. The fix for me was first to fix the router to channel 11. This fixed some other issues with netgear equipment a while ago, secondly, and most importantly, force WPA2 encryption on your connection instead of auto or (WPA or WPA2). You can try setting the encryption to AES only, but that didn’t work for me, it was only once I forced WPA2 that the issue went away. I am running mixed B-G-N as well. Now my Nexus One no longer kills the router. I am not sure whether or not my PSP will work now on my router since I remember it not supporting WPA2 a while ago, but it may be enabled with the current firmware. All of my other stuff can connect over WPA2 so it shouldn’t be a problem for me. If you have some stuff that can’t use WPA2, then getting another router might be the best option.