OP, only listen to people who actually own aero rims....if you have never ridden on anything aero, you can't really add to this thread.
OK, that said, I have a set of November 58mm's a set of Zipp 404 clinchers and a set of Reynolds Assault carbon clinchers. I think the reynolds are the best for all around riding since they are light (around 1450g), feel great, are stiff and are faster than my (granted) non aero Mavic R-sys wheels.
The 58mm november wheels are great since they are lighter than the zipps but seem to be as fast. I use them for crit racing and like them a lot. I use the zipps or reynolds for road races unless it's flat and calm winds.
I feel that the zipps and november's keep their speed very well and the reynolds are a bit faster to get there. For crosswinds the reynolds are the best since they are more shallow. I'm 5'10 and 168lbs...
I think the 38mm novembers are a great idea. I wa thinking of getting some for myself and selling the r-sys wheels. PLus carbon aero wheels look good.