I like the Craigslist and Ebay route for started bikes. Get Deore grade components as a minimum, LX, XT and XTR are big pluses. On a used bike (Craigslist) you should be able to get a 15 minute test ride. See how it feels and fits. If you notice any oil leaking after a test ride on the fork bail out immediately. Don't worry about Steel, CF or Titanium at this point. Just get a bike with solid components and a solid frame.