Hmm, scenes that have stuck in my head...Brian killing zombie Leighanne in SFTU, Nick in just a towel in Fight Me, MINE in It Stays With You, Nick falling out of the window in Why I'd Do It All Again, Peaches in Cronos Breach, Nick the Muffin Man and there's probably more but I can't think right now.
As for stuff I've written which has stuck in my head, Jordan and his bot flies is hard to forget, lol.