Hi all. I got virused up last week repairing someone's computer and had to reset. I am being lazy and asking the teeming millions here on CT because I have 9 sites to speed dial on Opera (browser) and over the years I have found some of the most marvelous websites through the people on this forum. I will start with one that I find is invaluable. http://toolhaus.org this site will search anyone's eBay profile for things. It will show you all of their negative feedback (on one page, not interspersed with positives), check for blocked bidders and much more. What sites do you like most?
I would probably say besides CT I use Numismedia the most (NumisMedia). Also CoinHelp is a great site for grading (How To Grade Morgan Dollars).
probably the PCGS website (www.pcgs.com) - I also subscribe to PCGS's CoinFacts (not free, but has a wealth of information). Also, I think we've posted this before, but Stone maintains a list of everyone's favorite websites - it's very comprehensive and well organized: http://forums.collectors.com/messageview.cfm?catid=26&threadid=607798
For me, it is Heritage. I use them to get pricing for just about everything (both buying and selling). I have also bought more than a coin of two from them.