How are you blowing it out? I assume getting a hole in the tube as you land off the curb. If it's a pair of holes on the tube, you're getting pinch flats from running the pressure too low. Check your pressures against the recommended pressure on the sidewall of the tire, and you might be able to fix your problem.
Mind you, sounds like you're just hankering for a new bike anyway. I'll let some of the guys and gals with more urban experience give you some recommendations. It'd help if you give us an idea of how much you're looking to spend, and what your intended use for the bike will be.
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