I dont use my Tablet at all in maya really, unless I'm using the artisan tools to do some serious adjustment where I need the control (a mouse usually does the trick), but I would say if youve got Z brush its a must! also in PS it makes a lot of things easier when painting textures 9pretty obvious really) as youge treally good control, as I said Z brush its a must as you get realy good sculpting control.

Ive got a simple cheap Trust tablet, think it was about £30, 512 pressure levels etc. really good for the price and more than enough for me. The mouse is rubbish though, if youve hover over a button and left click it the pointer jumps!! so its pretty much unusable!