Hummm again there are so many. I have to say monsters that make no sense (like the flumpf) never appear in my game.
However, orcs are overdone and are usually boring random thug encounters. They are flavorless monster that wait to get killed by the dozen. I dislike 'em.
On the other hand, Orks are AWESOME!!! Once you go green, you never really need or want to play another army...
D&D orcs=suck, GW orks=awesome!