I have a feedback of 3!! But, I live near Boston, and I am within an hour of 3 outlets, so I have only recently been lurking on ebay and bonanzle...
I have paypal setup with my amex, and I am still learning how to bid (been sniped a few times).
When I see that a seller won't sell to me because of low feedback or tell me to contact them first when I am looking through merchandise, I often keep searching and don't put it on my watch list, even if I am interested...
I have also contacted a seller who didn't request, to let them know that even though I have low feedback, I was a serious bidder. So, I think it works both ways.