I'm currently thinking of having a older VisualFoxPro database installation, migrated to the .NET platform, and am envisioning mySql, with a .ASP and Sharepoint front end.
I'm just at the beginning of determining what frontside functionality will be needed, but in general, for developing a 10-20 user access, small database, what hardware/software infrastructure would you use, and why. The functionality currently is just record access, sorting by fields, and a few reports, but additional functionality could be helpful and may be integrated in the future.

So you are looking forward to run a IIS based web server? Which Sharepoint server or services are you planning to use (version)? If as an example you plan to use SP 2007, you will be needing a 3GHz Processor (2 core) with at least 1GB or RAM (2GB recommended). MySQL is fine for 10-20 users. You have to use disk mirroring (best practice) and automatic backups for mySQL and IIS sites. There are plugins for ASP (I mean visual studio) to generate Reports and Graphs. This setting is good for best performance.