A lot will depend on the type of vamp list you are facing. A combat heavy vamp list will move fast and strike hard with cavalry and characters that will chew through saurus like a knife through butter (red fury + ASF + sword of might = up to 10 dead saurus/TG per round of combat!!). On the other hand, a grinding list will have large blocks of ghouls backed by corpse carts and likely a mortis engine (has a bomb that is 2d6 + turn inches area of effect that causes hits to your units and gives regen to vamp units). Lore of light can't go wrong as the two magic missiles each get an extra d6 hits and the buffs are all fantastic. As for kitting out, I would suggest diadem of power + cogitation + flaming banner for the slaan. If you can shut down/severely limit a vamp magic phase, it is usually possible to wipe out entire units through instability whereas failing to do so usually means all the casualties simply come back to life.
