Buffets Inc, I've mentioned them several times in my blog. They are evil for shutting down some great locations and laying off more then 400 excellent employees at the worst time ever.
AT&T for thier crap against ISP innovation, they are the ones who started the bandwidth caps, they have crappy cell service in both network and support, they are anti-net-neutrality, etc....
Adobe for making flash so bloated and insecure, thier software is very expensive, flash plugin is very unstable and causes lots of headaches, thier server backend software is problematic, and thier support for paying customers suck.
Ubisoft is the bad game dev with thier crap DRM where you had to be connected to thier servers constantly in order to just play a single player game! Many titles suffered from this.
Comcast for being a crappy cable company with caps and all kinds of mess.
Amazon for thier cloud hosting service failures taking out sites like minecraft, reddit and foursquare (sites I use) and not being very good about it. Also housed botnets as well that attacked other sites!
Rackspace lies to thier customers and says thier cloud servers are real cloud but they aren't. They overcharge
Hp makes crappy computers. They die constantly. I am an expert at experts-exchange and a lot of people there having issues with HP hardware.
Parellels and their struggling Plesk control panel. it has a lot of issues that give users headache and trouble and they take a long time to respond to support tickets. Many hosting companies are dropping thier control panel in favor of Cpanel.
Centova cast for not responding to customer complaints and they are being arrogant about it. 2CO was even threatening to shut thier payment processor account down.