Replace hard drive or add second?

I'm running out of space on my 120GB hard drive. I can't make up my mind if it would be best to simply add another HDD or replace my existing one with a larger drive. There seems to be equal pros & cons for either decision. Adding another drive would be cheaper, easier, and I assume hotter. Replacing the drive would be more expensive as I'd need a larger hdd and it would require reinstalling the OS. I already have an external drive for backup, so I wouldn't have a use for the old hard drive.

Any opinions or experience?

 

I'm personally against multiple hard drives in laptops, but it depends how much battery life you need. If battery life is not an issue, a second drive should be fine. If you want max battery, you could get a new drive, use norton ghost to image your old drive onto the new one, then take out the old one. It will be as if you never changed anything, besides the fact the hard drive is now bigger.
Since it's a 7200RPM SATA drive it can probably be sold for a few bucks.

 

Instead of replacing your hard drive, get an external hard drive and store your data on the external hard drive.