In the beginning the arduino was fine till there came such time where I wanted to find out what happens under the hood. I then did my home-work and at the end I was even able to program the arduino using assembler. With the gained knowledge I felt it was time I started messing with the big boys (32-bit ARMs)!. I bought the cheapest I can find in my country and it happened to be the STM32F4 discovery! I have to admit this isn't a good board for beginners because there aren't useful tutorial for it online, it's you, the libraries and datasheet. It was a steep learning curve (hope no one tries this unless you are up for it) but last night when I went to bed I had the board communicating with the onboard accelerometer. I will soon post a robot using the board.
Here's the image of the board i am currently using :
