For catalog or internet shoppers: do you buy from companies that only list a P.O. Box as an address?

It doesn't affect my decision. I don't even pay attention to the address listed.

No, it does not affect my decision to buy from the company.

I'm skeptical about buying things on-line and sending money to a Post office box, i have done it many times and have not been scammed, but all it takes is once!

When I think of PO Boxes and businesses, I sort of think of fly-by-night scam artist operations. I don't know why I do that, but having a PO Box address for a business is generally one of several characteristics of a scaming co. But I guess by the sheer number of small businesses, I also get the impression that its cheaper that way. Plus, I mostly do business with amazon or ebay when online, so thats not really an issue. I guess if went outside of that, I would just look them up on bbb.org.

I don't buy things online or in catalogs

I don't buy from them..my 'rents do occasionally though..

I am less likely to buy if all I have is a PO. I want to have an existing plot of land that I go to and kick their butt if they screwed me over. Just kidding, sort of.
Many sellers won't sell to some one with only a PO, so I feel it goes both ways.

That's not something I would be likely to notice. The company I work for uses a PO box for security reasons. The postal workers can't be trusted to get the mail to us. The small amount of mail that does come to the office, just gets dropped on the counter where anyone could steal it...

A P.O. Box costs about $30 a month to rent--maybe less. A company with a real street address has at least enough assets to maintain the street address. On the other hand, if I have heard of the company before, the PO Box address would not bother me.

It doesn't affect my decision to buy from a company.

No - it doesn't affect my decision to buy from a company...I don't even notice

.....

I don't understand what difference it would make.

No. Non-trivial companies do it all the time. Offhand, I just closed up a contract with Foundry Networks and the legal address in use was a PO Box.