still probably .com of course. but I think anything except .info or .biz not really sure how much it matters.
I'd go with a .com because people (in general) tend to trust ".com" more, it's also easier to market. Using an extension like .info may seem less trustful and "spammy" (even though it may not be).
For sure .com is the best for any kind of business, but if you find good name of other extension get it. Use keywords in the domain.