Based on my experience with an '05 C50LE:
Change the oil regularly (Ok, that goes without saying).
Always use 20w-50 oil, at least until the daytime temps drop below 35F. Some people have had good experience with Rotella Series 3 (diesel) oil.
It runs hot; keep the fan & radiator clean.
I haven't yet been able to see the coolant level through the inspection hole in the cover; I always end up taking it off. Get a good set of long hex bits for your ratchet wrench.
The initial valve adjustment is important, but 600 miles is too early, IMHO. I wanted to get mine done at about 1500 miles, ended up being closer to 3000. There seems to be a wide range of opinion on how often to it it after that. My bike started being a little noisy about 15K miles after the initial adjustment, at the end of this season. Re-adjustment is scheduled for spring service.
I had to remove the battery box to adjust the rear suspension, and ended up putting the suspension back where it was a couple weeks later.
Even though it's a V-Twin, it doesn't seem to shake anything loose.
On very, very hot days, the LED indicator will momentarily flash 'CHEC'. I've worked with the dealer for a fix, but it's hard to duplicate. Might not be an issue with newer bikes.
Most of the time, 10% alcohol gas makes it backfire like crazy.
Once you start riding it, you'll need a gallon of grin remover.
A couple of things that I rate as "must haves"
If you have a wind shield,
a set of these lowers
One of
these backrests
Have fun!