Just the other day I picked up my first Arduino.
The first thing I did was rush over to the Arduino website and start browsing around. In search of ways to play with it, it didn't take me long to stumble on this section,
Wow! I could not believe how many hardware devices there are here. Tons of contribution to this area has really expanded the capability of my $30 Arduino. Definitively well spent cash.
It's so unbelievably easy to use one of these things. Take for example, you want to print out a number to PC via the serial port, you don't even need to do any processing at all on the bytes to get it into ASCII form -it's all done for you.
unsigned char num;
This may seem silly to write about, but I'm used to writing tons of support code to make this soft of thing work. It really is plug-in and "play"!