You know, you can't beat the PIC24/dsPIC33 (16bit) or the PIC32 for price and performance...
I've used both for many project and have now standardizer on the PIC32..., no need to use a limiteted processor to do small project...
The development tools are free and solid, lots of demo code available...
a PIC32MX270F256B is in a dip package, USB serial, SPI, I2C I/O ATD ect... 64KB ram, 256K flash all for $4!!!
(there even a version of BASIC that run on the chip)
you can use a Microstick II from Microchip for $35 to program them or PicKIT3 for $45 ( on sale from time to time) (donot get a PICKIT2)
( if you have a .edu email address you can get at 25% discount)
their just no need to use a limited Arduino today!
tom lafleur