"n" is a hardware issue - apparently the Nexus 1 has the hardware but its not enabled (like the FM transmitter?)...I don't know if the Evo will have "n" hardware support or not. TBH though, I don't think its a big deal. I'd wager 99% of people use b or g.
nexus, hd2, and evo all have wifi N built in (I know nexus and hd2 has it, and evo should have the same card, so...)
The question is will they turn it on?
Wifi n is a touchy subject.
It should in theory increase battery life, and it does not seem to do it.
It should also allow faster download speeds, but that is a mixed bag too.
The simple fact is you should not be downloading massive files with your phone.
I have a 10Mbps home internet connection, well it is really a 12Mbps, but you never get all that.
The wireless router is a g/n router. So the 54Mbps is never really achieved because of the slow internet connection.
Now throw on top of that is the support issues and the cost of 50-60% more for the radio, it is not really surprising that they have enabled it.
Why try something that is not really going to be any help to anyone?
Unless you are downloading, gigbytes of information?
Even if you are syncing, you are limited to the write/read speed of the card, and even with a class 6 card you are not going to see any difference.
With a class 10 card ok, assuming everything is perfect.
I simply do not understand why faster is always better?
If it is not a n connection, it is all the sudden worthless, even though you will never use the speeds of a type n connection and there are not that many type n routers.
But faster is always better.
Understand, that for the majority of the people on the planet type g will do them just fine. Type N has some issues.