I generally like to go with names that are more traditional rather than trendy. I think a traditional-sounding name fits well with the type of stories I write, and my characters seem to respond to them, which is always a good thing.
I also consider how the name 'sounds' to the reader. I don't want my readers to have any trouble pronouncing my character's names. I know it always throws me out of the story if I have to stop and sound the name out in my head every time I read it. I think character names should help the story flow, rather than act as a distraction.
And then there are the names that I can't bring myself to use--those of my family and close friends. It always rattles me a bit when I encounter a book that uses the name of my brother or my dad for the hero, and I have a hard time enjoying the story because I always picture my family instead of the character. Just one of my strange quirks, I suppose. :)
What about you? If you're a writer, how do you name your characters? As a reader, are there certain names you enjoy and those you hate? How do character names affect your enjoyment of a book?