I grew up with long sermons. They were of the 30-minute variety. And in college not only were the sermons long, they had to be expository. I used to think that people who liked short sermons were intellectually lazy or something.
But now I know better. I am actually more impressed by a preacher who can make one really good point in 5-10 minutes than one who can make three points in 30. If your sermon requires the congregation to take notes in order to understand it, you are doing it wrong. I think it is more important to make a sermon memorable than to make it extensive.
Expository sermons are great, but I think that Bible study is best done outside of the context of a worship service. Sunday school and in-home Bible studies are perfect for learning what the Bible means. Sermons are a great opportunity for the preacher to exhort the congregation on other matters.
I love a short sermon.