I have just laid down some money for a Wacom Intuos4 tablet, I am hugely impressed with the Bamboo compared to what I had before but have since wondered how good the rather expensive professional tablets are.
I did try and demo one before I bought the Bamboo but couldn't find one to try and as it was a lot of money for me, I went with the cheaper option, of course it would have been better to have just gone that way initially but without being able to try any of the models it was too big a risk.

I have now found a very helpful store [link] who let me demo the new Bamboo model and the Intuos4, the new Bamboo Pen and Touch isn't much different (aside from it's touch functionality of course!) but the pro Intuos is in a different league...
Better pressure sensitivity x4, better lpi accuracy x2, 4 dial control modes (I use the single dial to zoom in and out a lot on the Bamboo), tilt function on the pen (probably not something that's useful for me), 2 more function keys and a much nicer pen design - rubberised grip etc.

"Investment" made! I figure from reputation, it'll last a long time and will help me work better. Won't get it for a while, my birthday is a couple of weeks before Christmas so I'll get in then but I've placed the order as I thought the helpful staff member deserved the sale