Just wanted to let everyone know that I did a purchase from another cointalk member, whom I didn't know, and everything went perfect. So it's not all doom and gloom!
I have had a few good experiences as well, the only bad one was at the fault of the USPS, but the seller was very nice about it and even though it was an insignificant amount of money he refunded it.
I have had nothing but good experiences buying and selling here. I think maybe once the seller rating system here starts being utilized more we should be able to commend those who are honest and at least figure out who may not be so trustworthy.
I have never had issue buying or selling coins or stamps online here or elsewhere. It all has to do with being careful. If you are buying, check out the seller every way you can think of... read feedback, read posts, only deal with sellers that have high post counts or nearly perfect feedback. If you are selling, get the money first and CYA on everything else, from item description to shipping details.