I am a true GSR shipper all the way. However, if there was no Grissom, I could totally root for Greg/Sara, cuz Greg is just too cute. But as long as Grissom is there, it's GSR without a doubt. I also like Cath/Warrick, and can see Greg/Nick, but GSR is really my OTP. In fact, I probably ship GSR more than I even shipped Mulder and Scully on the X-Files back in the day, and THAT says A LOT!