Everybody has a flash drive or memory stick; in fact, most of my friends have many. Flash drives are frequent giveaways at trade shows and conferences. They're wonderfully cheap and come in many sizes. So why buy one brand over another? Pexagon offers flash drives in 14 colors (in 512M, 1G, 2G, and 4G sizes) and they will engrave the drives FREE--no minimums; no setup fee. I'm thinking I'll buy a few for my backback with my name and number on them.
Seth Godin shares another commodity story in when the copy doesn't match the story. He notes that the copy leads off with, "The Bissell Healthy Home Vacuum is built like no other vacuum." Well, not really; the Bissell is just a clone of the Dyson but cheaper.
When your product category becomes commoditized, you can go cheap or you can go custom. Which makes the most sense for your business and for your customer?