Well Obviously the best Instance is Dragon Soul, one of the most Intuitive, Long, and Exciting Raids! As well as having great Cinematics...
my favorite instance is zul'gurub
My favorite instance has to be Naxxramas. The look and feel of that Raid is the standard that I use to judge all other raids.
Stratholme and End Time were both my favorites. I could run them all the time!
Zul'aman , best place to get your troll on
Gnomeregan, you never forget your first...
Kind of lame, but I think my favorite instance would be Siege of Ogrimmar. It just has a really cool vibe to it.
Ahn'Qiraj (AQ40) for sure, I miss vanilla!
Halls of Reflection. Hands down my favie.
FYI to those posting, the deadline for entries for the Giveaway has already passed. From the instructions above:
Ulduar, is still my favorite
My favorite instance was karozhan
Throne of thunder was AWESOME! :D
I think my most favourite instance was The Mechanar...Have run it countless times for that Sun Eater but never got bored of it...
that video is gud
Icecrown Citadel, by far