Yea, the Dinc wont see anything outside of the 2.4Ghz band. So if you have a dual band router that does wireless G in 2.4 and N in 5Ghz you won't be able to use N.
I just think that it was sad that I figured this out on my own and the HTC rep I talked to on the phone told me that the Dinc "should work" in the 5ghz range. She had no clue.
Like most people, I get way better signal. The phone would constantly drop the wifi upstairs before Froyo and now I have great signal. Speed seems to have picked up as well. Linksys Dual Band Wifi N - WRT610N, but only sees the 2.4 gHz band.