Using this library, ZXing, we have a project at school in which we’ll implement a inventory system using Android phones.
We aim to use an Android phone to be a inexpensive replacement to this:

I’ve read some of the warnings on the FAQ for certain phones. Is there a specific phone that Android developers prefer (with use of the ZXing library in mind)? We have to buy the phone ourselves, so we would prefer not to buy the wrong phone!
You want phones with auto-focus capability on their cameras. Some of the smaller/cheaper phones, like the HTC Tattoo, have fixed-focus cameras. Some tablets do not have a camera at all. Most Android phones have auto-focus cameras, AFAICT. Certainly, every one I have used has had one, and I have quite the collection at this point.
I’d watch out for phones running Android 1.x, not because of any ZXing problems, but if you are going to spend money, I’d invest in an Android 2.x device. One advantage of the Nexus One cited by Blumer is that it will get new Android releases as fast or faster than any other device.
Beyond that, and beyond specific problems cited on the ZXing site, anything should do, if it works with your carrier, is a color you like, etc. 🙂