I still buy all kinds of stuff off E-Bay. I think I've been burned only once really bad. I don't buy just car parts either. I've bought three 35MM cameras and accessories, a ton of O-gauge toy trains and parts, a bunch of autographed baseballs, and some certified collector coins. I even went with the Pay Pal charge card. I've got no complaints with E-Bay. You do have to be a careful shopper and read the advertisements and guarantees carefully. But I have found that E-Bay has been excellent about straightening out any problems I ran into. And they have been very few.
My Father-in law is a dedicated Craig's list buyer. I check them frequently, but their selection of cars and motorcycles seems to be pretty limited in my area.
I think that the crappy economy may be having an effect on all these places. Nobody is buying so nobody is selling. Maybe after the election and if the economy improves, E-Bay will get more active. I have found that items that are for sale are selling at dirt cheap prices. People may also be holding off on selling until it goes back to being a seller's market. If you watch the TV auctions at Barrets and other locations, the cars are no longer selling at outrageous prices unless they are very collectible. And even then, the sellers aren't giving anything away. Many times the seller won't take the highest bid, even if it's ridiculous.