Firebird is already packaged with the SAM Broadcaster installation file. Users who don't want to go through the hassle of installing a database server separately will appreciate this option.

However, there are a few trade-offs. Firebird is slightly slower than MySQL or MS SQL. As such, it's best to use another database if your music library contains more than 20,000 tracks. Also, while there's no problem integrating Firebird with dynamic PHP, ASP, or other Web languages, many developers don't have experience working with Firebird. So MySQL or MS SQL might be a better option if Web integration is high on your list of priorities.

MySQL

Power users should use this database. This means downloading and installing MySQL separately, and before you install SAM Broadcaster.

Installing MySQL is quite simple and worth the effort. It's fast and used for most open-source languages like PHP. Plus, the community edition of MySQL is free.

The only drawback is that it's a fairly heavy download.

MS SQL

If you want to develop in Microsoft technologies like ASP and .NET and you're already familiar with administering MS SQL, this database is an ideal option.

That said, it's costly and a heavy download if you don't have an installation CD. Luckily, there's a free version that could work out nicely for smaller radio stations:
http://www.microsoft.com/express/Database/