Last night I installed VB Express on my Tablet PC and had a play with it. Here are some observations...
First of all - integration with SQL Server 2005 Express edition (free) is pretty well baked in from the Setup stage (it gives you the option to download and install SQL Express as part of the install process) right through to the design stage. You can create a SQL Express database from inside VB Express using a wizard, and then use a data designer to work out the database structure, queries, views, etc
This will probably leave some people wondering what is meant when we say support for Database development is added in the Professional edition. Well the simple explanation for this is that you can create data driven applications with any Visual Studio 2005 product from express to team suite, however, if you want to create a SQL 2005 Integration Services project, you'll need to use Visual Studio 2005 Professional or higher
Because of the data capabilities (you can also hook your application up to a web service), the express editions are pretty powerful - you can develop almost anything with them for the desktop or for the web (Visual Web Developer Express).
I also downloaded the Tablet PC SDK 1.7 with the view to learning a little about tablet development. This is really easy, and using VB Express and the Tablet SDK I had a small Ink aware application running in just a few moments.
Rather than post the code here, I'll point you off to where I went for details and some other places that are useful for you if you want to get into this stuff (for free no less)...
Working with SQL Express from inside Visual Studio Express editions (note that if you use the Express release candidates, the SQL Express Manager wont install - this will be fixed soon - in the meantime use the data designer in the VS Express edition of your choice to do this).
Tablet PC Development 101 (part 1) - Getting Started, part 2 - adding context awareness and part 3 (which is where I started) - stroke and recognition. This is a great guide to get started with the TabletPC SDK - the samples are C#, but you can follow the concepts and convert to VB easily enough if you need to.