Welcome to MacRumors.
Your first lesson today is to Search the forums before posting a new thread, as this topic has been covered many times.
The MacBook and MacBook Pro use a Serial ATA (SATA) 2.5" hard drive, 9.5 mm tall. It is compatible AFAIK with all 2.5" SATA hard drives on the market today. Brands to look for are Seagate Momentus (5 year warranty), Western Digital Scorpio (3 years), Samsung Spinpoint (3 yr?), Hitachi Travelstar (3 yrs) and Toshiba (don't remember their model name)
Make sure its the SATA model you are pricing, and make sure you get the full manufacturers warranty in writing. You don't want a pull, OEM, gray market or re-certified drive with zero or one year warranty.