Gratz, I'm an AVR fan myself. Most of my stuff is on hold right now for various reasons but I have an STK500. Once you outgrow the AVRISP I'd recommend getting the Dragon dev board. It does require a little bit of work because it comes without any headers soldered on (for user customizing) but it has an absolutely massive list of features. The AVRISP does everything you really need except for parallel or 'high voltage' programming. But only a few chips require that for certain setups.
What kind of projects do you have planned?