I went ahead and installed a K&N last night. Went to AutoZone and they ordered one for me and had to to me the next day. Figured I would be ahead to pay retail and have it quickly, rather than save maybe $8 on the internet, then pay shipping and still not have it for 5 days.
Gave me a good opportunity to open the airbox for the first time, as well. Very clean in there, just a bit of oil blow-by, which I cleaned up. Also took the time to wipe down (dust) the underside of the tank and the various hoses and bits around the airbox (I like a CLEAN bike, inside and out).
First impression is that the engine runs a tad smoother, but I'm guessing that's largely because the original filter was pretty dirty. I'll get a better idea after I take a weekend ride.