~15 data sets w/ 25k rows & ~20 columns + quick  one time reports = Access VS SQL?
Access is a perfectly fine database system for small scale individual-user apps. Here are some criteria for shifting:


Multi-user applications. Access doesn't do concurrency very well, so a multi-user database - particularly one where multiple users are making modifications to data - will bring Access to it's knees.
Requirement to support advanced SQL functions (windowing, partitioning, MERGE, triggers etc).
Large datasets. Access used to have hard limits on .mdb files at 2GB (IIRC), and I found the likelihood of corruption increases rapidly when the total DB size gets over a gigabyte. (Note that I haven't used Access 2010, so I don't know if things are better now in this regard.)


Note that if you have a front-end built in Access and just want to shift the database away from JET (Access's internal DB engine) onto a "proper" RDBMS, you can do so by migrating the data across and setting up linked tables inside Access to the new data source.