Well...I have to put in a plug for Photoshop Elements!
I use PSE3 and I love it! I have never used DI, but I have heard it is easier to learn. PSE probably has more of a learning curve to it.
However, it is almost as powerful as Photoshop. There is tons of information for Photoshop here and all over the web. And 90% of that info can be used for PSE as well. PSE uses all of the PS brushes, custom shapes, layer styles, but costs a fraction of PS.
That's my 2 cents worth!
(you do realize we're all going to have a different opinion
)