Im also one of those who started with a unified Undead army "back in the days". When VCs were first released, I simply went with them because they were there, Khemri was not.
I actually didn´t quite like the first VC book, so I switched to Khemri once the mock-up list appeared in WD. When the second VC book came out, I switched back, first trying out the Blood Dragons, and then - finally - settling for the Necrarch. Evil, maniacal and undying sorcerers raising huge Hordes of the Dead trying to destroy all live, all the while trying to increase their own arcane power... fun! :mrgreen:
I still have my old TK army, but couldn´t really get myself to play them again in quite a while... besides, the VC background has been much better explored by GW in novels and such - Tomb Kings could be more interesting (there´s more than enough interesting stuff in egyptian mythology about the Dead and Life after Death), but I doubt that GW will ever go there. A pitty, but it leaves me more time for my Vampires.
Oh, and then there´s the Zombies of course! Lots and lots and lots of Zombies!