I have a Linux Fund mbna credit card that I got at LWE 3 years ago. It has a picture of tux on it. I'm not much of a linux advocate, and I have no idea if the fund is doing any well, but I like the credit card because about 20% of the time I make a face-to-face purchase I get this reaction:
"Oh, isn't that cute!"
So that doesn't necessarily make the logo cool, but it does make it somewhat attractive.
Only once have I gotten this reaction:
"Oh, cool, linux!"