I think as long as you do a soft-reset (or whatever it's exactly called), your content shouldn't be compromised. I'm not sure about the hard-reset.
If you go on vacation or so, try putting your stuff on internal memory (it's quicker than the memory cards) and in case you have to reset, have a memory card with the same content as backup. That's what I would do if I were concerned about having to reset.
Well, I only did completely shut down/reset my unit after flashing the firmware with the russian hack. Otherwise, I never had to reset yet.