According to Microsoft Research study, objects smaller than 256K are best stored in a database while objects larger than 1M are best stored in the filesystem. Between 256K and 1M, the read:write ratio and rate of object overwrite or replacement are important factors.http://research.microsoft.com/apps/pubs/default.aspx?id=64525
Thus, I would recommend to consider mixed approach, or store all files on a file system. You can choose database you are most familiar with. MSSQL Server Express could be a good choice, if your database size does not exceed 4G.
[UPD] as was correctly noted below, DB size limitation is 10G