This effect is fairly simple to simulate in Photoshop, providing you know your way around the program. Instead of me explaining how I do it, see a very simple version which explains the technique in a very detailed fashion.
I agree completely. I'd like to add to the discussion: too many shots I've seen lately look awful due to obvious use of a graduated filter. Unless that's become a fad... but I still think it looks artificial. That said, I sometime use gnd's, even coloured ones, but only when their use will appear natural. One downside to gnd's is even in raw format you still have the enhancement as part of the file.