Okay, I sell laptops like 40 hours a week so I should be able to help here....
CPU-Since you multitask a lot you must get a good dual core proc, either a Turion 64x2 or Intel Core Duo. If you really want some power you could go the Core2Duo route but I think for you that's overkill.
RAM-1gb is the minimum, If you can afford it get 2 (the max in nearly all notebooks)
HD-At least 80gbs, depend on how much music and movies you want to store.
Video- Don't bother with Intel Integrated graphics, they're very poor even for your needs. You'll never be able to play a new game on your lappy and they'd be kind of a waste. At least get an ATI x200/ nvidia gefroce 6100 or 6150 or equivalent integrated graphics. It's not a whole lot more to get an actualy dedicated card and I would encourage you to do so for playing new games.
For portability reasons (big, heavy notebook, shorter battery life, etc) I don't usually recommend a 17" screen. 15.4" is great for most people. What is your price range here?