What kind of siding is this

If you can remove one panel carefully you might find the manufacturer stamp on the back. It will narrow down the search down a little bit. Otherwise just a small sample would be nice to have when visit the stores. I've seen websites on the web that identify manufactures based on the sample that you send. Both Lowe's and Home Depot sell some vynil siding. Not a huge selection.

Honestly, it doesn't have to be exactly the same. The previous owner used a similar siding on the addition and i didn't notice until i had to replace a panel.

Have you thought about using hardy board siding? You can get the same look and feel of wood without the risk of mold or termites. The price would not be much different than a good quality wood siding. It is not that difficult to install either, so labor cost should be no different. It is also easy to remove and replace incase there are any future problems with the house(ie electric or plumbing) that would require you to have to remove your siding.