Nope. I left the Linux desktop for OSX not because of aesthetics but because of the freedom from frustration that OS X gave me. Design isn't about making things more pretty, it is about improving the way a system works where the human part of it meets the machine part of it.
Linux distros just haven't put in the man-hours to make it a functional desktop for many.
The main problem, I'd say, is that there really isn't much of a reason to switch. People who buy a computer don't have any incentive to go through the with hassle.
If computers came with Ubuntu pre-installed I'm sure people would use those without a second thought.
However, the package management still needs to improve. One realizes that upon upgrading from one Ubuntu release to the other particularly if you have a bunch of software installed from PPAs. It would be unreasonable to expect a typical user to be able to fix the problems that it leads to.
While `apt-get` is great, you realize the limitations when you need to resort to `dpkg` when the package management is left in a broken state due to the occasional mess created upon removing a package.
I wish somebody from Canonical were looking at this thread.
I am not sure the desktop needs conquering, we have more than one option and Linux won't make it unless it can get apps that people just have to have
Which is hard for it to get. Developing an app for desktop Linux means targeting a small group of people who are willing to endure frustration in order to run code whose source is available. Unless you are have some other revenue stream besides your customer, you can't make it more than a hobby.