RL Classic The granddaddy of them all, and probably my best all-around scanner. Right price (free) and right features (lets you turn on your flash as a light for iPhone 4 users).

Scan - QR Code and Barcode Reader The dark horse up-and-comer in this list, I may end up switching to this one over my vaunted RedLaser. Why? This one has done a better job of scanning non-traditional and off-color (not black and white) codes than any other reader I've tried.

AT&T Code Scanner: QR, Data Matrix, and UPC Barcode Reader A lot of my friends use this one, and say it's great, but I just can't use one that's branded - I don't want AT&T to know what I'm scanning.

Shop Savvy More than just a good QR code reader, Shop Savvy scans barcodes as well, giving you the best price for that item around you or online. Kind of a Swiss Army Knife with an extra screwdriver.

Microsoft Tag Not a QR code reader, but part of a new print code system by Microsoft called Tag. Good to have this one in your Utilities folder as well, just in case.

Qrafter - QR Code and Barcode Reader This one both reads AND generates QR codes, but you have to pay for the code generator. Seeing as how I can do that for free using a number of web apps, and I'm not sure what you would do with a QR code generated on the run since you probably can't print it, this seems like an unnecessary toy.