Open or semi-open headphones simply sound better. You're going to be limiting yourself to lower performers of any price range if you keep wanting to have your computer's fan silenced when you put the headphones on, instead of just letting the music slightly overpower it. Or hey, just put in a smooth ball-bearing 120mm fan for your computer and it won't be loud anymore either.
That's certainly up for debate. Just as some people prefer the Sennheiser sound, some people prefer closed headphones. The Denon D2000 might fit your wants.