I was thinking about developing in C, against AmigaOS' native libraries, or BlitzBasic2, since I messed around with it in my Amiga days (and I still have the original package and manual).
Now that you mention it, I've seen AmiBlitz (although German only sites and docs) and I really have no ideia where to start programming for the Amiga...
Although coding my Home Automation client for the Amiga is a hobby project, I'd like to use the most flexible language/API (running on AmigaOS 3 is good, but being able to easily "port" to AmigaOS 4 and AROS and MorphOS would be very nice). For all the other platforms (Mac, Windows, Linux, Solaris) I have the main client, written in Java.
I still have to investigate a bit. I should be receiving my "new" A1200 and A4000 next week...