Regardless of your ultimate interest Arduino (and the AVR microcontroller family in general) is a decent place to start :)
If you do have previous development experience, you'll probably want to move past Arduino pretty quickly. You can pick up an Atmel STK500 development board for just $79, and either use it with AVR Studio or the open source toolchains (avrdude, avr-gcc, avr-libc, etc): http://store.atmel.com/PartDetail.aspx?q=p:1050007
For engineers, the idea of using a wii nunchuck to control color LED's is trivial. For an artist or a design it can be world-changing. And our local arduino group does just that :-)
They're doing a nice job and deserve the positive recognition.
Here in the U.S., SparkFun and BDMicro have built nice niches in this market.
SparkFun's Pick and Place Machine: http://www.youtube.com/watch?v=tn0EKtLOVx4
I had her get me the inventor's kit from sparkfun since it seems to come with a decent # of starter parts, and has a collection of projects you can do with them. I haven't been able to stop playing with my Arduino and I'm alredy ordering more parts and X10 controllers and such, and I only got through the 4th project before I started doing my own thing like having it communicate with the computer.
In a way it reminds me of Rails, in that it inspires a world of DIYers to build whatever they are dreaming about.
I've had the pleasure of introducing many artists to the world of programming via Processing, and am always amazed by the widely creative works that are produced, almost off the bat.
Arduino beautifully extends the same capabilities to analog and digital circuitry. Many artists are greatly appreciative of the new channels of creativity that these two project (as well as others) enable.
The most interesting variants for me are the ones with wireless communication. Great for making remote sensor networks.
