I have a Dell Latitude D600 and I'm wondering what kind of hard drive can I get that would work?

Hi there.  I have found some harddrives for you.  Depending on the GB you want or if you want an internal or external harddrive, I have found the following for you. 

I found the first harddrive on eBay for $69.75.  It has the following features:
Max. 160GB formatted capacity per disk.
ATA Security Mode Feature Set.
Ultra DMA Mode 5(UDMA100) Compatible.
ATA S.M.A.R.T. Feature Set.
TuMR/PMR head with FOD technology.
SilentSeek™.
Support Automatic Acoustic Management(AAM).
NoiseGuard™.
Load/Unload Head Technology.

Second one is from Staples.  It comes with free shipping for $184.99.  It has the following features:
40GB or 60 GB
4200 RPM
Plug and play installation
Axiom's system specific Branded Notebook Hard Drives offer guaranteed compatibility with your notebook computer.
Available with a caddy for easy installation without having to remove any screws.

The third recommendation is from Dell itself.  It is an external harddrive.  It has the following features:
Offers a storage capacity of up to 250GB
Compatible with Dell Latitude D800/ D600/ D500 / Inspiron 8500/ 8600/ 9100/ 500m/ 510m/ 600m / Precision M60 /(D400 external bay only) Laptops