Difference in CS4 and CS4 Extended (student?)

[Robbo]

CS4 £500
CS4 Extended (assuming studen version) £150

Whats missing?

Also, what things can you do in CS4 thad elements cant do? along the lines of RAW, cloning, healing brush etc

 

[swanseamale47]

The extended differences are mostly not that usefull to normal photographers, theres 3d, video, and some image analysis.
I don't use elements but the raw colning and healing should be pretty much the same.