Can I upgrade my e-mac to OS X Leopard?

Just closing out the last details regarding burning discs. -R and -RW(rewritable) can be confirmed by you when you click through Apple>About This Mac>More Info>Disc Burning; you will see CD-Write: -R, -RW. -RW are generally more expensive for the luxury of the rewritable feature.

I actually have a Seagate 500GB FreeAgent; however, how can you pass up on a Western Digital 1TB for 109.00 at Staples. Plus, the top Quantum designers who gave Apple such reliable hard drives a decade back are now working for Western Digital. The hard drive business is a small world. Other brands would include Iomega, Verbatim and HP. Make sure it is new out of the box and that it is for a Mac; match up the connectivity either USB 2.0 and/or Firewire. They all make PC and Mac compatible versions or they can be reformatted for either. Why bother reformatting when you can by it formatted for a Mac.
Good to go.

I have the Education-only eMac model from 2004 (identical to the USB 2.0 model, but with a 1.0 GHz processor, no modem and a CD-ROM drive). It came with Mac OS X Tiger preinstalled, but a while after I got it, before I accidentally broke it (am still waiting for my new power button to arive), I managed to replace the stock CD-ROM drive with an old HP dual-layer DVD/CD writer drive, installed the PatchBurn utility (it worked just fine), then upgraded the machine to Leopard. No problems whatsoever with the installation. I did upgrade iLife '04 shipped on it to iLife '09 just to be safe (though, being a G4, I had to replace iMovie '04 with iMovie HD 6). Leopard ran perfectly stable and nice on the eMac, though it was a tad sluggish, since I only had 512 MB of RAM. I swapped one of the 256 MB modules with a 1 GB module, boosting it up to 1.25 GB of RAM, and that helped quite a bit. Just my two cents on this topic.