I use Fujitsu tablets. I got a great deal on refurbished tablets from their eBay store.
If you use the Search feature on this website, and set it for the past 6 months or so, you will find lots of past threads on tablet PCs and Dragon Naturally Speaking, including links to other websites.
I would recommend either buying DNS 9.5 or looking into one of the KnowBrainer medical vocabularies. Tom Hamilton from KnowBrainer posts here from time to time.
Here's a good website with lots of tablet PC reviews:
http://www.tabletpc2.com/