I was in the exact same position as you. I really wanted one of the 23's but couldn't find a way to justify that extra 500 quid. I work predominantly as a web designer, and only do the occasional bit of print work. So really the colour correction was not the most important factor.
However, my current 17 LCD was fading, not to such an extent that it was useless, but it was becoming annoying to work from. So I decided that it needed replacing. I went for the 20 instead and I couldn't be any happier. The new displays are awesome in every way, looks, stability, brightness, colour, sharpness etc...
I have kept on my old 17 and set it up with Windows colourspace and I can test designs by just dragging them over! Way better than sending it through a network and spinning the chair round.
I have more screen than I know what to do with! When the 17 is not testing designs, its acting as a palette monitor so I can get a full 1024 x 768 canvas on a single screen with all my PotatoShop panels open at the same time!
Here is a pic of them together. I know the old one is butt ugly but the new Apple one more than makes up for it!
