I plan on purchasing a 200gb hard drive for my xbox and I was wondering if I will need an aftermarket modchip to be able to backup my games. If so, could you please point me in the direction of an affordable one? Thanks!

You will need some sort of modification done to your xbox, either a modchip, software mod, or a TSOP flash. Depends on where you live as to whom I would recommend.

well if it's only a modchip that I need, I'm pretty comfortable installing myself. I live in Orange County, CA (Tustin).

you will have to have your xbox already modded before you put in the hdd (in addition to placing the Xbox file system on the drive)

You can also use a game save exploit that only runs Evox to get copies of your c, e and eeprom.bin file. Then make a xboxhdm disk and use it to build your new drive and install the exploit with. This will leave your original drive intact and unmodified and your new drive modifed and ready to install into your xbox. If you use this method, don't forget that you will need to lock the new drive before putting it into your xbox.