Very important point. That being said, it's not an one-or-the-other issue.
I can do 100% of my UX/UI design in OmniGraffle and then implement it as black boxes on a white page and have a well thought-out easy to use site.
On the other hand, there are so many "pretty" sites that are really hard to interact with.
So, both are important - It seems to me that in the "web 2.0" world a pretty design will get press and get people in the door, and good UX is what will keep people using your site.
I can do 100% of my UX/UI design in OmniGraffle and then implement it as black boxes on a white page and have a well thought-out easy to use site.
On the other hand, there are so many "pretty" sites that are really hard to interact with.
So, both are important - It seems to me that in the "web 2.0" world a pretty design will get press and get people in the door, and good UX is what will keep people using your site.