I want a good lead, that can learn Stealth Rock.
Swampert is a pretty standard one, he's got good bulk, and his typing leads him with one weakness. Mamoswine can deliver some pain with it as well. If you use legendaries, a popular choice is Azelf.
Ferrethorn is a good one though I have found that everyone expects him and start with a fire type that said he is still my favorite lead