I've followed the optimization steps in these forums,
I've got no pictures/movies/music and very few programs on my bb yet the available memory hovers around 14xxxxxx - 15xxxxxx and I'm having to constantly delete old messages & browser logs and check the memory, to avoid another "automatic delete everything and reset settings" episode. And I can rule out ever installing any fun new programs or anything.
I've never had a smartphone that I've had to worry about the memory before :-(
Just let this be a warning to any potential bb / pearl buyers out there!