Yay! 50 Mounts!
Hit the 50 mount mark tonight. As an achievement award/reward, you get your 51st mount via mail after hitting the 50 mount achievement mark!
Albino Drake!
50 mounts is easier than it sounds for a level 80. Basically, getting faction with each of the capital cities, plus the netherdrake faction gets you access to about 6-7 mounts per faction. Next, add in all of the alliance (or Horde if you prefer) flying mounts. Supplement here and there with a battlegrounds mount, a few Northrend mounts, and a zhevra for referring a friend, and that about does it.
I was able to get faction with each capital city at the rate of about 1 city per night. I basically just ran every quest for that faction from level 1 to 20, and that does most of it.
The netherwing faction was a bit more challenging, but there's tons of guides out there, and doing those at level 80 is a breeze.