Buying New Hard Drive, What is the Drive Size needed?

Hello All. Im Buying a New HDD for my Macbook because Of Space/Speed Reasons. I Found on on new Egg. Now I need to know the Size that i should get. They All look 2.5". But i Want to make SURE its the Right Size so im not Screwed.

Macbook Model:

Macbook Pro 5,4

Intel Core 2 Duo 2.53 GHZ

NVIDIA 9400m Graphics

4 GB DDR3 1067Mhz

15" Screen.

Thanks!

NewEgg is OK, but I prefer buying from the Mac specialists here. You'll get the correct drive size and great customer service.

With all the electronic and computer sellers\distributors in Tokyo, you can't find one to buy a hard drive from?

Regards.