Wacoms are pure awesome. I threw away my mouse and replaced it with a large Intous and have not looked back. And I've got the near-magical Wacom Cintiq 21" pen monitor for digital drawing & sketching. Productivity raised by 300% -fun factor by 1000%.
May I suggest you invest in a Connectix SpacePilot? That one was a real eye-opener for me. It just makes moving around in 3D space so much more intuitive and fast. If you're using 3D professionally I'd say you'll earn back the retail price in a month just by increased productivity.
There's a bargain price ($18 when I write this) on one of the old ones (same as I've got) on eBay now if you're quick:
http://item.mobileweb.ebay.com/viewitem ... 9864724024