My DM is running us through A Dungeon Magazine adventure path. The first part had us going against a bunch of skulks. They are pretty easy to defeat............once you are able to see them. They have a hide of +22!! If I see another skulk (wich I doubt I will with thier +22) it will be too soon. They kept getting the drop on us, but we aere able to survive by having two clerics and a wand of cure light with us.
If you are a mean DM you could give them a couple of levels of rogue or assassin