Prior to 1992 you could not compete in the Olympic games with a MacBook Pro whereas you could with a MacBook. However, amateur status is no longer a requirement. Happy notebooking!
All kidding aside, they pretty much said it all.
Larger screen
Dedicated + Integrated Graphics vs. just Integrated
Faster CPU
Large HDD which is changable
Firewire
Expresscard Slot
Only high end MacBook has backlit keyboard
Heavier
Speakers
Seriously doubt it will have any affect of that certain part of the male anatomy. It's a MacBook Pro - not Enzyte.