Linux HA and little microcontrollers

Now that I'm done with my book and I sat back and looked at my HA setup. I have quite a hodge-podge of bits a pieces of different things. While the PLC portion will probably remain the center of my HA system I'd really like to start making more use of the microcontrollers like my HCS II. The HCS II is based on the Zilog Z80 (a Z180/S180 which is a microcontroller Z80). The central controller is called the SC (Supervisory Controller). It has a bunch of digital and analog I/O. Other modules called comm-links. The first comm-links were based on the 8051 controller. Later ones were based on Microchip PIC chips (particularly the 14 bit 16Fxxx and 12Fxxx chips). Today we have a long line of chips to choose from. There are 8051 derivatives, lot of PIC chips to choose from, AVRs from Atmel, TI has the MSP430 family, Zilog has the EZ8 family and we're starting to see ARM chips in tiny pin outs that make it easy to use as microcontrollers. Many of the tools (assemblers, IDEs and compilers) to write code for these chips are available as Open Source projects. Some are available under Linux and BSD in addition to Windows (I'm tired of being hog tied by Windows). It would be nice if I had Microchip's IDE under Linux (hint, hint, nudge, nudge). I think I'll start with a few comm-links attached directly to a serial port on my Linux and see what I can come up with. Nothing too fancy just simple digital I/O for now. This would let me use simple LEDs to perform testing.