A "when you don't want overcalls" hand?

[shiburu]

I'd like to clarify that I should've raised at the end here.

I raised in the small blind with AK and got three or four callers, including the button. The turn and river were checked all around; it was one of those hands you just had to bet to win. I was in seat six, and when river fell, the button in seat five picked up his cards and I saw he had A8: no pair for either of us. It was checked to him and he bet his A-high. Knowing I had him beat and that everyone else would probably fold, I called and won the pot. Should I have raised to protect my A-high against a low pair in this medium-sized pot?