I have a 10 min rule with my PP (cos I am old and slow on the computer) - basically I shot in RAW and use the RAW converter in PSE 9 to do a very quick adjustment and then in PSE I do a levels, brightness and contrast adjustment, sometimes a colur curves adjustment and an Unsharp sharpening (I hope that is the right terminology) and thats it.
Sometimes with my underwater shots I will use the 'Dust and Scratches' filter to remove floaty stuff (backscatter) from the water.
I know one guy who will spend an hour min on a photo in PS just to enter it in a comp - not for me.
Karl