I've been pondering this a lot ... well, okay, not really, but I thought I'd throw my two cents in. If I were compiling this list, I'd include these milestone-y episodes:
126. Matthew vs. all the ghosts.
155. Elizabeth tells Laura to skedaddle. She doesn't. Fighting fire with fire ensues.
248. Barnabas locks Maggie in a coffin (not for the faint of heart).
405. THE CURSE!
569. Tom and Julia get frisky.
748. Magda gives Quentin a dose of (well-deserved) curse.
955. Angelique powers up and takes out her frustrations on Quentin and Maggie.
1012. In the murky and disturbing world of Parallel time, Quentin welcomes Barnabas to Collinwood.
1150. Au revoir, Roxanne.
1202. Bramwell and Catherine discover the wonders of pre-marital pelvicness.
I thought I'd try to include representative episodes from the majority of time periods ... I honestly can't believe that the curse episode wasn't included on either of MPI's latest collections, but what can you do.