Honestly, I think the San Antonio Spurs are the only team in the league with a legitimate shot at beating the Warriors in a 7 game series, and even then the odds are against them.
Problem with the Clippers is that they aren't a very good defensive team outside of DeAndre and CP3, Blake isn't a very good defender and Draymond Green gives him all sorts of problems everytime they match up, and when the Warriors go small, DeAndre Jordan is almost like a cancer for the Clippers when trying to match up with the Warriors' small lineup. He doesn't have the low post offense to really pound it inside the paint on the smaller guys, almost, if not all of his field goals come from alley oops and easy dunks from Chris Paul, and his free throws...Dear Lord his free throws... that's self-explanatory at this point. I mean he had 20 rebounds against the Warriors the other night and CP3 played great, but the Warriors were in control most of the way through and won the game just fine.
And as for the Thunder, let's be real... Kevin Durant and Russell Westbrook is all they've got who are efficient and effective on a consistent basis, even then Westbrook has trouble shooting the ball, the longer that series would go, the heavier load that Durant and Westbrook would have to carry and the more the Warriors would have the advantage. The Thunder just don't have the bench or the defense to beat the Warriors 4 out of 7 games.
To beat the Warriors, you need 4 things:
a) Intense Lockdown Defense
b) A Strong Low Post Offensive Game
c) A Deep Bench
and d) Great Coaching
The San Antonio Spurs have every single one of these things. They have the #1 rated defense in the league. Combined with LaMarcus Aldridge, Tim Duncan, and David West their low post offense is very strong and capable of pounding the Warriors' smaller guys, and could even force them to go big with enough success. Their bench is just as deep, if not deeper than the Warriors. The Spurs second unit of Ginobli, West, Patty Mills, Jonathon Simmons, and that other European guy, I forget his name... they're got enough to be a starting lineup on an 8th seed playoff roster. And they currently have the best coach in basketball right now, the great Gregg Popovich.
So if any team can knock off Golden State in my view, its the Spurs.