Since you're asking here are my recommendations. Try selling your mid range pipes here first. Forget about the high grades. I've never seen an expensive pipe sell here, but you will get a nice bunch of compliments about your high grade pipe with hopes that somebody (else) will actually buy it. Pipes at $200 more or less, and below, may actually sell here.
If you don't mind doing the work and you don't want to pay commission then definitely eBay. You will need to take great pictures and also write a clear, complete and concise description. Presentation is everything. You are unlikely to make the kind of money that well established eBay sellers get, but you will get what the market, at that moment in time and space, is willing to spend on your high grades. I've never had a problem selling on eBay. If you're worried about selling your pipe for nothing you have options. You can set a reserve for the bottom amount that you are willing to take, or you can sell the pipes as a "buy it now" and negotiate directly with a potential buyer.
If you don't mind selling at wholesale in exchange for ease, then sell to a dealer. Besides Pipestud, I'd absolutely recommend Marty Pulvers and Mike Glukler. I know all these guys and they are scrupulously honest. And if you would be happy with a store credit, try Smoking Pipes.
One last eBay option is to sell to one of the better known eBay dealers like coopersark, treasurepipes, or greatestates.
Just keep in mind that all of these other avenues will be paying wholesale for your pipes, as they are entitled to make a profit and will have their capital tied up in your pipes until they sell them.
Last but certainly not least, image hosting sites. Avoid Photobucket. Aside from their predatory site practices, they charge $500 a year for giving you the ability to post your images to remote servers. Sometimes you might be able to post an image for an hour or even a day, before their system detects the remote server and kills your post. My personal choice is imgur, which has a well developed simple interface to use.
The last piece of info is that the market for high end pipes currently is very, very soft. High end pipes at high end prices are not selling. So keep your expectations reasonable.
