Snails happen. I don't think you can completely avoid them in a planted tank. If the snails thrive in my tank, I figure I must be doing something to promote them. I do have some loaches for a bit of control, but they don't really bother me.
I guess my favorite "free" snail is the MTS (or Malaysian Trumpet Snail). They burrow in the substrate during daylight, so they help, to an extent, with anaerboic substrate problems and you don't see them much.