@akratic: Ha, yes I know what you mean. But I've been very happy with my ebay buying... It's the selling that would make me nervous. Ebay/paypal seem to side with buyers over sellers almost always now.
*Make sure there is adequate feedback and length of time on ebay.
*Make sure they have sold bullion during that time... You don't want to be the first to trust a seller with high end money. The higher volume of bullion usually the better. If someone has only sold a few, they might be trustworthy but they also might not understand the importance of shipping insurance. In well over 50 purchases I've never had to claim insurance, well done USPS!... Still, it's a judgement call. Some of my best deals were from low volume sellers.
My bad experiences:
*Amateur seller listed coins as immaculate, they had milkspots from gloveless handling... Silver was already up 10% so I didn't want my money back.
*A long time 100% positive seller, with much experience in bullion, sold 50 lots (huge red flag, learned my lesson) claimed that he would ship in 30 days when the mint delivered his order. Anyway silver shot up, and coins were never delivered (he must have been betting on a decline). Ebay (not paypal) came through with a refund in 2 days. I was pleased and impressed.
*Once or twice had junk silver and silver eagles sitting unattended on my porch.
-overall my gold buying experiences have been 100% positive, silver >98% positive.
-no taxes or fees.
-fairly anonymous... Although USPS employees probably know what's going on, I doubt they care. What else weighs 1 oz and has 1800 in insurance?

Importantly, you can use a credit card without a fee, unlike the dealers in my area. I've been using this one for 5% cashback:
http://www.aarpcreditcard.com/Default?CELL=66J9
Also, 2% ebay bucks, which occasionally will jump up to 4%... Combining those two, you can often get in under spot.