There are a number of ways to flush Magento cache, with slight differences. I have always been a bit confused about these and often end up overdoing it when deleting the cache. This my understanding of it as it is but maybe someone could correct this and answer my questions. I am hoping this question could be a source covering all aspects of cache ... I haven't found another question here which answers all questions in one.
Selecting individual lines using checkboxes and selecting refresh Surgically deleting a particular area of cache.
Pressing "Flush Magento Cache" Same as selecting and refreshing ALL from above (BTW anyone know why this operation is referred to as flush and the previous as refresh?)
Flush Cache Storage Same as last option but also includes some cache which may be shared 'by other applications' What applications for instance?
If anyone else has any other questions they might want to edit this and add the questions.