I started programming '51 family of MCU nearby 1998. Next I worked with AVR, NEC V850 and today I work with ARM Cortex M0/M3/M4. Primary with NXP's LPC8xx,LPC15xx,LPC17xx and LPC546xx MCU's, but some others can't be a problem for me. I program in C language. I prefer Keil uVision IDE. I don't use RTOS.