I have a Lansky diamond set, some DMT cards, a 3 stone Arkansas set, and a piece of flat ceramic, as well as several home made and commercial strops, they all get some use depending on what I need to sharpen. I even use my diamond bits with my Dremel tool. Ben and 1442 have the right idea, oft times less expensive works just as well. What works best for you is what to use, if it fits your budget.
Hawkdancer