I have had trouble with this reversion problem in the past, and found that often it had to do with the permissions of the files and/or folders for the alternative theme or icon set that I had selected. Aurora based themes are particularly susceptible to this problem -- I have no idea why.
If you haven't yet corrected the problem, you may want to investigate this.
Thanks for the helpful idea. Fortunately though I think I solved it, sort of.. After getting the libindicator error in the xessions-errors file I did tried something. Opened up Synaptic Package Manger and searched libindicator. I then installed every package that popped up (roughly 7 that weren't already installed) and the problem has appeared to disappear, lol. I'll continue to monitor and update this thread if something changes. So far so good! Very happy! Now to get back to setting up my media server...