There are many agenda programs and almost all of them are excessive to cover your needs. Thus Custom Addressbook 5.0 is very practical as it is a simple agenda (with basic options) that lets the user personalize it totally, adding fields and different categories that you want it to have. Thus you only store the essential information for your daily use. It also has a useful internal searcher to look in any of those fields and categories.
It lets you export the agenda data in TXT, HTML, XML and even CSV formats.