avr-at90s1200
Hi Pharaoh of Egypt!
If you are familiar with 51 series of processor then you can use AT89C51 of Atmel - I have used this crystal on 34 MHz with external generator. So, you will have (1/34000000)*12=~0.35 uS per instruction.
PIC16F84 has 4 takts per instruction, so if you have 20 MHz pic, then you will have (1/20000000)*4=0.2 uS per instruction.
If you will need more quickest processor, then use AT90S1200 or better AT90S2313 it is working on 10 MHz (even up to 12 MHz) - you will have 1 takt per instruction, so it will be 1/10000000=0.1 uS per instruction.
If it is too slow for you, then get Scenix (Ubicom) microprocessor - it has 1 takt per instruction and is working up to 75 MHz (or even up to 100 MHz in some conditions), so it will be: 1/75000000=13 nS per instruction.
If you are going to make decoder like 3chip, then best choise will be AT90S2313. It has enough power and memory to decode Tocom's style TV signals (I mean SSAVI coding).
Best Wishes! klug.