If any of you are like me and hate when you go to a comic store because you're looking at a cover and wondering if you own the book, I totally fell in love with the comic collector apps that Collectorz.com puts out.
On the PC side you catalog your comics and then export it to your mobile device (they have various mobile apps like for the iphone/ipod touch, android, etc.). So when I am at the comic shop, I can look up the series and see that I have it/don't have it. It has made life so much easier. And having seen guys at comic shows carrying spiral notebooks around, mine fits in my pocket and has a picture of the comic with all its information right there - all stored within the phone with no need to connect to the web while out.