I like this thread! Thank you for thinking of it.
I actually started watching CSI during mid-season 5 because my once favorite Thursday night TV show (ER) turned into pure crap once all of the original characters left, and the writers started to focus all their attention on one know-it-all nurse. The show has been in the toilet ever since.
It's interesting that when I was still an ER fan, I always put down CSI because I thought it was too violent and gory, and I resented it because it overtook ER in the ratings. Talk about a radical change of mind! Once I laid eyes on Greg, I was hooked. I'm having a hard time trying to remember the episode that he caught my eye, but I think it was "Spark of Life". During that same time, I caught the episode "Play with Fire" on Spike TV and stayed interested ever since.
I enjoy most of the characters very much, but Greg keeps me watching.