photoshop

I currently have PSPX and after doing a trial version on PS CS I would like to buy Photoshop as well.

Could someone explain the difference between Adobe Photoshop Elements 5.0 and Adobe Photoshop Creative Suite 2.0. Why is CS more exspensive?

Any insight would be great, thank you.


(P.S. Sorry is this is slightly off-topic, I will delete this if you wish.)