Ok tablet users, help me decide between the Intuos4 Medium and Large models...

I've never used a tablet before, so there'll be a bit of a learning curve...

We will be using it mainly for 2d drawings and shading, etc. but I'll also be using it for Moi :)
General computer use will still be done with the mouse.

Is a Medium too small and restrictive to draw with?

I have a 24" 1920x1200 monitor (Dell 2407WFP with an 8-bit S-IPS panel).

Thanks!