As it happens I am running Launcher Pro and do deploy the app hide feature.  While that isn't what is making them vanish, as I literally am having to redownload and install them from the market, this was actually a pretty insightful solution considering what little info was given, and easily could have been the case, as I am pretty absent minded sometimes.  Hopefully this may save a couple others who, like me, sometimes forget smaller details.  Marking as Solved.