i used to think that photoshop and fireworks are just as good as each other, but a soon realised that photoshop is superior in every way, go with photoshop
I am using Photoshop because it has more friendly interface and many powerful tools to use of. And Adobe is quite famous because of their acrobat reader, flash, installshield etc. (thats my own opinion when I choose Photoshop) :P
I haven't used PSP in a while, in fact since i learned how to use PS, but i remember the first times i opened PS i got scared and didnt know what to do and i ended up closing it and because of that i grab PSP which was more user-friendly(it was like version 5 or 6), at least for my eye and i learned there so much, that made my jump to PS a lot easier, so i'd recommend PSP for the begginers