This was touched on in a different thread, but it's something I've wrestled with for a while. I mainly run the biz from home. I do some of the heavy manufacturing work for my products at another space, but I do not own it... It belongs to someone else who lets me share it. So using that as a contact is a no go, because I wouldn't be there most of the time anyway.
Last year I took out a box at a PO nearby for my domain reg. I did it because I had some nut post all my whois info after somebody asked if anyone had purchased something from us and if they liked it. Why on earth somebody replied with my whois info, I have no idea. People are crazy. I also tried my actual address for a short time and had a few people come to the door. Between that and the whois incident, I just don't want my real address connected with the site.
The PO I got the box at is not close enough to be handy. The closer one has no boxes available. So because I don't have time to run over to the box, I have not used that address on the site. I didn't want to risk someone sending a payment and having it sit there. Plus, I sort of feel like... the paranoid types are not going to be happy with a PO anyway. In fact, it would probably just make them more suspicious.
I found a retail mail box store that offers a street address and also has a phone option where you can call and see if you have mail. About $20 a month. I'm thinking I might do that.
Then there's the situation with the phone number on a small biz site as well, but that's another deal.