I have had good luck with HP all-in-one printer/scanner/copiers. The software that comes with the scanner is important too. If you can find a scanner that comes with Adobe PhotoShop Elements, I recommend you get it. That is a great piece of photo editing software. By itself I think it costs $100 commercially. The educational price used to be around $20, I'd check on that to be sure.
For our COV projects, however, I recommend trying to use your camera and photographing your pictures you were going to scan at full resolution (10 megapixel) and use the macro setting. (It looks like a flower) You can usually get pretty good results that way.