Finally, after a long time of answering forums posts and my own posts here.
Ben Armstrong (or VirtualPC Guy fame) has posted a series of articles regarding snapshots and snapshot behavior.
Please, read and enjoy. These are not going away any time soon.
Where are my snapshot files?
What happens when I delete a snapshot?
What happens when a snapshot is being merged?
Why does it take so long to delete a virtual machine with snapshots?
What happens if I start a virtual machine that is merging snapshot files?
Should virtual machine snapshots be used in production?