Without a doubt I miss Randy Rhoads the most. I know for sure he made Ozzy, and Quiet Riot, even though he wasn't there for too long. I only wish he could have been around a few years longer, to hear the madness he could write after learning more advanced classical theory like he wanted to.
Everyone misses cliff, as they should, for he would have made metallica an infinitely better band... but I miss Randy more.