Comment Re:32 GB in my Mac Pro (Score 1) 543
While I agree with your post in general, your example of "a file server with a small set of files" isn't the best example of a case for a SSD. If that "small set of files" can fit into RAM, then a SSD isn't going to buy you much benefit outside of initially being quicker to read the data into memory. However file servers really are data set dependent, so without knowing the details, it's hard to say what's the best upgrade.
RAM is definitely not always the most beneficial upgrade for personal computers. Adding RAM definitely suffers diminishing returns to scale (which is generally true with everything, but RAM benefits seem to diminish more rapidly). It has been my experience that RAM beyond 4GB is much less beneficial than a SSD for typical personal computer usage. For example I upgraded my personal laptop from a 7200 RPM drive to a SSD and from 4GB to 8GB, and the SSD improvement is significantly more noticeable.