A spinner is probably a good idea. But I recommend Tentacruel instead of Starmie. Tentacruel is bulkier, and most importantly, absorbs Toxic Spikes. Then it can spin away Stealth Rock, Spikes, and Sticky Web. So:

-Tentacruel w/Black Sludge
Nature: Timid
Ability: whatever you can get
EVs: 248 HP, 244 Defense, 16 Speed
Moves: Rapid Spin, Scald, Substitute, Sludge Bomb/Toxic/Toxic Spikes
You have to chain breed to get Rapid spin on a Tentacruel (breed a Squirtle/Wartortle/Blastoise with Rapid Spin with a Kabuto, then breed that with a Tentacool), but its very nice. The set gives it the most overall bulk.
Then let's put a special sweeper into your team, to try and round it out. What to put in....
Lets try Volcarona, because Volcarona is boss (can't wait to transfer mine to Y when the PokeBank is released):

-Volcarona w/Life Orb
Ability: Flame Body
Nature: Modest/Timid
EVs: 252 Special Attack, 252 Speed, 4 Defense
Moves: Quiver Dance, Bug Buzz, Hurricane/Giga Drain, special-based fire attack of your choice
Its very simple: Quiver Dance, then render everything to ashes. If you can wait till PokeBank, you can get one with Giga Drain, which is a great move for it. If not, Hurricane works fine. It also pairs well with Tentacruel, who spins away the rocks it doesn't like, and resists water attacks for it.