I recommend buying the MacBook and purchasing a separate retail drive. Switch out the drive yourself and place the original drive that came with your MacBook into a 2.5" external enclosure. Doing this will save you money.
Also, buy the ram retail for big savings. I purchased RAM through Newegg.com and saved boatloads. I've kept my original Apple ram for just in case I take my MacBook in for service, so I don't get warranty issue thrown at me. Actually, the only thing that should come up with warranty is retail RAM is not covered under Apple's warranty - basic or Applecare. Apple RAM is covered.