The best advice really is to download trials first. Both corel and adobe offer one month trials - I suggest you download them and see which one you prefer.
I personally use Paint Shop Pro as when I used the trial versions, I found it much easier to use. It also does text on a path which as far as I am aware PSE doesn't do. Although it isn't something that I necessarily use on every LO, it was important to me to be able to do it. Other than that, I think PSE is very similar in its capabilities.
Photoshop CS has far more capabilities than PSE and PSP, with the price tag to match!! Whether you would need all the bells and whistles that it has, I don't know - II have always managed to do what I want to do with my LOs in PSP, including designing, although with designing, somethings probably took me longer to do than if I used PSCS.
Sorry, maybe a bit biased, but as it is all I have ever used, I do prefer PSP, but others prefer PSE/CS
I really do suggest you download the trial versions b4 deciding.