What database you use depends very much on your individual requirements. Here are some notes to bear in mind.
Most people already have some experience of Access - it is very easy to work with. It is free with MS Office. You can either use access files or draw data from SQL Server using OLE DB. You can upsize access to SQL Server. Programming in Visual Basic for applications (VBA) - very similar to VB. MS Access was designed as a database system for small scale office use. It was not designed for use as a database server, although it can be used in this mode for simple use. Although Access may be capable of handling the sorts of query volume you suggest, at least in the short term, you do need to consider scalability (SQLServer scales better), Web site integration (SQLServer *probably* integrates better), enterprise access to the data (SQLServer will better enable intranet access to the data, etc). Data structures are unlikely to be affected by a move to SQLServer. The general rule seems to be that if you plan on more than 25 concurrent connections then go SQL instead of Access Cannot add so many entries.
Client-server technology. It is more scalable for busier/larger sites. You can connect to it remotely using ODBC and MS Access has an option to link to tables - use a front end. It is fairly easy to use, support from Microsoft Visual Studio programming suite (can work on it using VB). SQLServer integrates with a Web site better. Data can be output in XML. However it is more expensive. More to learn than with access.
High-powered software. Mixed platform. More complex to use
It's free. A combination of Perl or PHP and MySQL is pretty straight forward. User interfaces not as good.