I'd use Forretress for it's many physical resistances.
Have a Dusclops to stop Rapid Spinners (No one uses Rapid Spin in-game, but who cares, you might be fighting competitively someday. Plus, Dusclops is a great wall).
Tyranitar's Sandstream makes sure that opponents can't recover the Spikes damage with Leftovers.
Swampert is great for Fire resistance.
RestTalk Zapdos takes care of the slight Water weakness you may have with the previous team members.
Another fast sweeper (i.e. Starmie) fills in the last slot and cleans up any weakened opponents