programming (basic , c , cobol, java, you name it) is different than programming for microcontrollers as Peter said earlier.
first you need to understand electronics and how to interface your microcontroller to the outside world. then you need to understand your microcontroller and how it works, how the hardware peripherals work and what they are. the only way as a begginer to understand how the thing works is to use assembly.
Sorry when i started the subject about c vs assembly i thought all people on the forum where electronic engineers and they have at least a knowledge of one processor family assembly language.

"besides, once you have used assembler you never want to use anything else :-) "

thats not true, each job has its tools and you cant solve differntial equations with assembly, the good thing about c is that its the closest high level language to assembly and it compiles hi level language efficiently, and it got its popularity in the embeded world because you get best of both worlds(hi level and low level).
mahmood