Hi,
for me the Copplestone ones are still unbeaten when it comes to lively poses and the number of different guys available. I have painted quite a large party (~ 120) and sqeezed quite a few celtios and even chronopia in, as well as any other fitting these nice 28mm sculpts.
If you want to include a few "lesser" ones the foundry ancient germans will fit in as well (also made by copplestone...).
As center pieces I have got a Grendier Mammouth and an Maidenhead Wollen Whino.
cheers Thomas