Bored with SQL Server? Looking for something new, and/or cheaper? Got a bunch of interesting alternative databases:

I've mentioned REL and VistaDB previously. VistaDB has made some significant improvements since then (including a 60% reduction in engine size, to 400KB!). It's geared towards .Net apps as a replacement for MSDE or light SQL Server duties. Go check it out.

Cloudscape was developed by IBM and they released it under an open source license last year. You can get the download here. It's written in Java and is a relational DB. Looks interesting.

PostGreSQL recently released version 8.0 and now includes a native Win32 version, so no more Cygwin troubles. This one is pretty damn solid and has a bunch of cool things SQL Server doesn't.

FireBird has been around for a bit, it's based upon the Interbase engine that Borland maintained and released to open source. Looks interesting.

Except for VistaDB, all of the above are freely available under various open-source licenses too.

And I won't bother mentioning this one again. :)