Looks OK, except your H-bridges won't work. You have emitter follower pullups (Q1, Q3, Q5, Q7), so the emitter can only get to 0.7v below a logic "1", minus the drop in the 2k base resistor, which can be sizeable unless you have motors that only draw a few milliamps - not likely. You can solve that problem by eliminating the base resistors in the emitter followers, but a logic "1" from an LS gate is only about 4 volts on a good day, so you will NEVER get more than about 3.3v at the emitters, even with little or no load.
One solution is to run your entire circuit off 9 volts, and use CMOS CD4000 series logic. Then your emitters can get to 8.3 volts. Keep in mind that the 2N3904 is not a high current transistor, and the beta goes to hell above 100ma.
All your switches should pull to GND, with a pullup resistor to +V. Switching to +V does nothing on TTL gates (and, I believe, LM556), because the inputs float high anyway. You can switch high and use pulldown resistors, but they waste a lot of current, because the logic low input current in a TTL gate is much higher than the logic high input current.
If you change to CMOS logic, input current is essentially zero, so you can do your XOR switches either way, so long as you use a resistor to pull to the other rail. Never leave CMOS logic inputs floating. Leaving TTL inputs floating is not a good idea, but you can usually get away with it.
The only other comment I have is that the datasheet for the IR receiver (from Radio Shack) didn't show the need for a pullup resistor, but it probably won't hurt anything.