Would you recommend that I buy another chargeable battery for my Nikon D5000 or buy a battery grip? If all goes well, I'm planing on doing something over the Chrisfmas holidays that would require me to take well over 1,000 pictures in one day. If I get another battery, I could have one charging and use one, etc. What are some benefits of using a battery grip? What do you think? Thanks for your help!