I've always been a fan of Canon products, and the CanoScan LiDE110 is fantastic. Not only does it not have its own power cord, but it's plug and play! The only real complaint I have about it is that the software that it comes with is lousy. Fortunately, good old Windows Fax and Scan is fine for the photo quality scans I need for listing items on EBay and Listia, and Paint is good enough for my sketches. Best of all, this scanner literally sits right atop my computer and is extremely light and portable with fairly good scan quality even on the lower settings. It's all that I need.
I'd give this product a 9/10, mostly because I wish it came with better software. At the time, it was only $49 on Amazon. At that price, you could never find a better quality stand-alone scanner for a better price! Unfortunately, the price on this model has skyrocketed to around $90-100. Still, it's a great product, even at that price point. There is a less expensive model, the LiDE120, which is actually the #2 selling Document Scanner on Amazon (as of this writing) in between two $400 scanners!
If you want super high quality photo scans, this might not be your product. But if you're just someone who needs a simple scanner like I do for casual projects and listing photos, this is an amazing value.