MacBook Pro Upgrading (Ram & HD)

I have a 2.33 C2D MacBook Pro with 2 GB and a 120 GB HD.

I wanted to get a new HD. I need more space, but thought I could use some extra speed too. Is a 7200 RPM HD going to be worth the extra money and speed, and how much worse is batter life?

And I wanted to get more ram. I was going to get rid of one stick, and replace it with a 2 GB stick. Since all Macs are 667 mhz, will the computer work with the stock 667 MHZ DDr2 and a different companies 800 mhz DDr2?

I know the 800 will be reduced to 667, but I can't find any 667 mhz, and I don't want to buy Apple ram because its a rip off.

 

I just looked on newegg

Thanks.