Due to circumstance, I can't shoot much higher than f/4.
This limits me for now to a handful of my lenses, none of which (save one) were even remotely expensive.
Wide apertures are incredibly useful when you need isolation or don't have the time (or ability) to get your sensor clean in the event of problems.
As far as clarity goes, I don't really have issues with fuzziness. If its a touch fuzzy, simply beat it up with some selective post and/or reduce the image size and you're usually set.
Here are some recents, all wide open (or at most a stop down) at whatever the minimum aperture was for the lens.
As someone mentioned, a lot of times people mistake a narrow depth of field for an image not being sharp. IMHO, if you can't manual focus with a narrow DOF or your more modern lens isn't autofocusing spot-on, then a wide aperture lens would very much be useless.
I've discovered over the past year however that even 'trash' lenses tend to still be sharp even stopped down, or at least are sharp enough for most uses. Of course if you're going in to view them at 100% and pixel peep, then you'll probably have issues with almost any photo.