Rikki, still early days, but here's my initial reaction, a thread I posted on Saturday.
http://www.synthzone.com/ubbs/Forum37/HTML/016923.html

I'm working on the right speaker system to use at home. I need something small and good looking since the keyboard is in our open plan living room/dining room/entry. I have have narrowed it down to the Logitech z4 or z2300. They both sound good (I tried them both on the Tyros 2 and they both sound better than the Tyros speakers). It might come down to which speakers are easier to mount on the wall (and that's looking like the z4 right now.

I'm planning to take my time on the transition since I have set up a program that I'm going to play on gigs for the next month already on the Tyros. Maybe I'll start by taking the Korg to church in a week or two, depending on how I get on with the setup.

Graham