I believe that PSE has had Content Aware Fill added to its repertoire since PSE 9.
Layer Masks have been available in PSE for quite some time (I have 7 and I believe it was in PSE prior to that).
Actions may be useful for someone who does the same process time and again. I don't do a lot of batch photography (such as studio shoots where the dust spots are in the same position everytime or the lighting needs to be adjusted the same way everytime). I am unsure where Actions would be of significant use for the normal photographer? What else can be done with it? (no such thing as a problem, merely an opportunity to improve).
I've heard of Smart objects and don't understand them (haen't had time to google).
Selections? Lots of ways to do so already (quick select, select wizard and so on), what is the extra value of the Pen Tool?
As to the others, what do you find is their significant value over other methods (if they exist). Do they make a large differrence in your workflow, in the quality of the image, in the manipulation of the image? If so, it may be worthwhile to upgrade, but I don't know (hence my earlier request).
Thanks,
Graham