Every knows that HorrorClix has some great figs that can be used in 25/28mm zombie games. They can be rebased and painted easily. Others have posted about them; VampiFan has some great posts on his blog about converting all sorts of clicky minis, not just HorrorClix, for use in a zombie game. While I've done quite a few rebase/repaints, these are the first zombie figs I've done.
Of the three, the Irradiated Zombie fig on the right of the first pic is my favorite. The sculpt is great, especially considering it's a clicky.