I dislike blogs on definition alone. Its a meme website for so many people.
I DO enjoy reading those that are written by people who aren't overly into themselves. Most of my friends are programmers and post useful bits and pieces of whatever project they are working on. Its neat to see an update like whats new with someone you know (especially when you all go to different schools). They can say what they've accomplished lately, places they've been, a few thoughts and ideas, funny story or two, big purchases like a car etc.
The ones I dislike are the "I had pie for lunch. I cut myself sometimes because... I feel down". The blogs that list mood, music and fabricated depressing rants are horrible. Oh and the ones that try to evangelize and say "I'm god because I run a blog and can subject you to my bullsh!t opinions"--those ones suck.
I prefer when someone proofs their entry and runs it through a spellcheck first. As informal as they are, I still think of them as "published" for one reason or another.