Okay, being somewhat more serious here...
CSI has the 7 year itch. Sara isn't signed on for next season, making her character SOMEWHAT at risk. Her relationship with Grissom also puts her in the potential line for a evil story arc, and she hasn't really had an intense story arc this year (outside of the Grissom relationship, which was shown a bit at the start of the season and then pretty much left as quiet as can be).
My feeling is that if they expect CSI to run a very long time (and judging by the ratings, it isn't going away) then you can look for more characters to get developed into main players, and for one or two of the current players to get "moved upstairs" where they can make less intense appearances. I am thinking that one of the current CSIs might get bumped all the way up to replacing Eckley, and I wouldn't be shocked to see Catherine pushed past Grissom as she has played political ball so well every time she is in charge. This could happen, example, as a result of Grissom and Sara's relationship being revealed, putting Grissom out of the running for the top job.
I can also see an upcoming story arc to explain Nick a little better. We rarely if ever get anything about Nick outside of the office, and I have a feeling that he is due for some non-trauma related character development, to give him some more depth and more angles to be played.
So my bet is that the season cliffhanger involves the Grissom / Sidle relationship, and how it plays out regarding who will run the lab next season.