I'm still waiting for my copy of VS 2008 Professional, but I've caught a very nice freebee from VistaDB. It's called VistaDB Express Edition and you can look at http://www.vistadb.net/blog/vistadb-news/vistadb-express-release/ . It is a very interesting database engine because:
1. It's written in managed code
2. It's tiny (yes it's darn tiny)
3. It's powerful despite its tiny size
4. It's SQL language compatible with SQL Server Express
5. It get updated regularly
6. The databases created are also very tiny
There's one but: although its SQL Server compatibility, not everything works at this time like CURSOR and FETCH.
Despite of these small limitations this DB is far better than Jet/Access and even SQL Server CE!
You'll hear from me regarding this database!
You can download it at http://download.vistadb.net/download-evals.aspx and give it a try