I am the sole sysadmin for a small firm of about 50 people, and I have been asked to develop an in-house application for tracking job completion and providing reports based on that data. I'm planning on building it as a web application. I have roughly equal experience developing for MySQL, PostgreSQL, and MSSQL. We are primarily a Windows-based shop, but I'm fairly comfortable with both Windows and Linux system administration.

These are my two biggest concerns:

• Ease of managability. I don't expect to be maintaining this database forever. For the sake of the person that eventually has to take over for me, which database has the lowest barrier to entry?
• Data integrity. This means transaction-safe, robust storage, and easy backup/recovery. Even better if the database can be easily replicated.

There is not a lot of budget for this project, so I am restricted to working with one of the free database systems mentioned above. What would you choose?