Just thought I'd pitch in as well 3DShay about tablet size. I had been using a Genius 9x12 tablet for about a year and a half. Never used any other tablet before, so I had nothing to compare it with. Anyway got ZBrush 4 and found that my old Genius wouldn't, no pressure sensitvity so I decided on an Intuos 4.
My biggest headache was what size to get, having always used a large size I was really hesitant in getting the small version (couldn't stretch my budget to a medium) so decided to scale my work area down on my Genius to match the work area of the small Intuos 4. After about an hours work I discovered I only really used a small portion of the Genius.
Anyhoo, in simple terms, bought Intuos4, plugged in, played with ZBrush and PS (both worked brilliantly) replaced standard nib with spring loaded nib (and grinned at variety avaliable) and fell in love with the feel and pressure. Binned old tablet, walked off into the sunset with new Intuos4. Cue cheesy music!