Whats wrong with your current tubes? I would use those unless their old. Otherwise any good quality tube will work. Specialized has a couple of good tough tubes including the Airlock Tube that has a sealant in it that works far better then Slime, in fact Slime won't work at all above 65 to 70 psi. Or they also have the Desert Protection which is the same as their regular Airlock but has a thicker thorn resistent area that contacts the tire. But as one poster mentioned these are heavy.

If you want the 2nd best flat protection then turn to Specialized again with their new Roubaix Armadillo Elite combines lightweightness and superior flat protection. OR for the best flat protection then Specialized All Condition Armadillo Reflect Tire is it, though heavy at about 475grms very little can penetrate either the tread or the sidewall. This last tire is a great commuting tire because you don't have to worry about road conditions and whether or not your going to make it to work on time! It also has a reflective stripe on the sidewalls to aide in your visiblity to motorists.