When I was getting started in microcontrollers, I used a BASIC Stamp before messing with Arduino.
I had this kit:
http://learn.parallax.com/whats-microcontrollerIt is a great platform, and has been around longer than the Arduino bootloader. I haven't used their Propeller boards though, which would probably be better suited. The reason I switched to Arduino is because the BASIC Stamp I had, is you guessed it, coded in BASIC [well PBASIC but meh].
Any uc you get is going to be round about the same. The ports and data bits might be diff and the libs diff too, but the concepts and all is all the same.
Here is a video from EEVBlog, great channel for electronics btw, he doesn't go over Parallax but he does do Atmega VS PIC so it's worth a watch if your getting into this kinda stuff.
http://www.youtube.com/watch?v=DBftApUQ8QIGlad to see more interest in this kinda stuff. You can do some fun things with WiFi and Eth and all on the embedded level.