Hey, I'm looking for a 4 to 16 decoder. I got sn74154n, the only trouble, however, is that it outputs LOW - if I input 0xA, 10th output will become LOW, and the rest will be HIGH... Does anyone know the opposite of that? I need a certain pin to be HIGH and the rest LOW

All I can find are the same way. Inputs in one way but the outputs go low when active. You can always stick an inverter at the output to change the swing around.

are those inverters pretty fast? because my inputs will change once about every milisecond.

The 74LS series switches in less than a microsecond. I have used them up to 20 MHz.

74LS04 (I think)