This is the mac-daddy of all breadboard-capable AVR chips. With a whopping 128 kb of on-chip program flash, 4 kb EEPROM, and 16 kb of sram, you can graduate from LED a few LED's to full blown embedded applications, and even keep it on a breadboard! This is also the chip that powers many of the "DIY" 3D printers and CNC mills (Including our own in house one). It comes ina 40-pin DIP form factor.
This is the blank chip. You will need a programmer, a crystal, and a couple of load caps, at a bare minimum, to use this with a breadboard (and a power supply of some sort).
If you are more interested in using this chip with a bootloader in an Arduino-like fashion, stay tuned, we're working on putting something together.
You can get a ton of mileage out of this with Atmel Studio and/or gcc. Atmel also has a lot of application notes and reference designs here.