You can use the "Aquamend" kind they sell at Home Depot and the Loctite marine kind sold at Lowes. The main thing you need to look for is that they don't contain any metals.
As other have mentioned Aquamend will work, but it's not as easy to use as some of the aquarium brands. It's a little 'stickier' and not as strong until it sets up. Also, the white color kind of stands out in a tank.
I agree. The white is the only issue I have with it. Almost everything in my tank is secured right to the rockwork, I hate frag plugs. The white stands out a lot until it gets covered in coraline.