IG: Special Troops (Steel Legion, for example), just the fact that they are unique - I do not know of anyone who actually plays with any of these armies.
Orks: Looted Wagons - the Custom made ones are the best!
Demons: Blood Crushers, they simply look amazing.
Space Marines: Contemptor Dreadnoughts - ya they are FW models but they are awesome.
Nids: Warriors and Raveners are my favorite models from the Nid line, its a shame that GW cannot seem to make them work.
I am always a sucker for Terminator models too.
Originally Posted by neilbatte
if you squint the Sigmar stuff doesn't all look like the love children from a Necron and Blood Angel orgy.