Depends on if you want to play hardcore competitive or not...
If you do, then you're pretty much stuck running Ghouls for core, Grave Guard in special, and your choice of Rare units. They're kinda cookie cutter in making lists. They are pretty competitive though, if you use their cheese build. Grave Guard with the Banner of the Barrows, Great Weapons, a Wight King with the Drakenhof Banner, and a Vampire Lord with the Helm of Commandment...you get GG with 2+ to hit, 2+ to wound with killing blow, and the whole unit gets 4+ Regen. It's just about the nastiest deathstar in the game, but it's really vulnerable to magic (Purple Sun, Dwellers) so you have to bring a Dispel Scroll.