Which monitor calibration tool to get?

Hi,
I have a Lenovo T500 (Vista) and a Dell Dimension 8400. Both using LCD screens. I use PSE 6.0 for PP.
What calibration tools that you would recommend?
If this question came up before, my apologies for repeating it as my search did not turn up.
Thanks in advance.

I'd use an X Rite Eye1 Display2, but then I would say that because it's what I use.

It seems more straightforward than the Spyder range from the problem posts I've read here about them. It has a very good help giving advise and guidance at every stage which is running live at all times on the RHS of the screen. Also X Rite have proven to be very helpful.

But be careful with Vista. Research the known problems with this OS and how it reacts to ICC profiles.

Thanks so much Lowner.
After reading some posts and research some names of the products, I've decided to go with Spyder 3 Pro.
Each calibration tool has it's own strength and weakness. For my own use, the spyder 3 will be more than enough.