Chrome gets usability issues right. Things like their tab closing behavior, the almost total lack of dialogues, one click bookmarking, etc. are all really great. But Chrome is not a beautiful app. Its toolbar icons are fairly childish, its tabs just a bit off.
I'd say that trend holds through most of their products.
I guess it's totally subjective and therefore fairly meaningless, but I think Chrome is the most visually appealing of any browser right now. This is partly, I guess, because its primary virtue is minimalism, but the parts that are there are beautiful, I think.
For instance (in 9.0.597):
* Mouse over a tab, and move your cursor back and forth. The whole tab is highlighted, but there's extra brightness around the cursor.
* Similarly, look carefully at the buttons on the main bar, or at bookmarks, when mousing over. There's a subtle brightening over a fraction of a second, instead of an instant-on hover effect. Don't believe it? Compare it to mousing over the "+" new tab button, which is instantly highlighted to its full degree.
* Tabs, when re-arranged, slide to their new positions instead of snapping.
* URLs lose http://, and everything after the first "/" is very slightly grayed instead of black.
* Every corner is curved. Every dark edge is under-highlighted, so tabs seem to "float above" the rest of the UI. Those back / reload buttons seem to be recessed black icons instead of buttons - until you mouse over them.
* "Active" chrome elements - active tab, browser + extensions, and bookmarks - have a light -> dark -> light transition through all of them. Inactive tabs are noticeably closer to a solid, darker gray, though they to have a slight gradient. It helps unify the active tab with the applicable chrome seamlessly. You'll also notice Firefox 4 has adopted similar visual cues for tabs.
All of which adds more visual cues to what things do, and easier hierarchical organization at a glance, while maintaining extremely minimal clutter.
There are also a couple things I dislike. Like how utterly massive the bookmarks-in-folders on the bookmarks bar are. Almost twice what other browsers have / via the menu. Glitches in Web Inspector. Excessively-useful hidden preferences. But overall, there's a frightening amount of polish in Chrome.
Edit: See: Suprematism (http://en.wikipedia.org/wiki/Suprematism), De Stijl (though they liked bold colors) (http://en.wikipedia.org/wiki/De_Stijl), arguably Bauhaus (http://en.wikipedia.org/wiki/Bauhaus), "International Style" ( http://en.wikipedia.org/wiki/International_style_(architectu... ), all of which came before the increased business in art of the 40s-60s, which came before "Minimalism" proper in ~1965. And this is primarily in America & Europe - other areas have had their blends as well.
All of which was pretty heavily influenced by the traditional Japanese aesthetic, which has a pretty strong focus on Minimalism-like attributes.
Minimalism as a positive thing isn't just reactionary. It also serves to bring subtle details into focus, and to emphasize the craft (ie, crafter's experience / quality) as a whole rather than individual details.
Unstable Docky from PPA (The stable version is basically identical). Docky is pure butter. It is a few features down from AWN but it's MUCH more consistent (had problems with clicks registering in AWN in weird places) and is gorgeous. It really takes advantage of the SVG icons from Faenza.
The toolbar at the top is standard gnome-panel with Cardapio replacing the standard GNOME Main Menu. Cardapio is easily my favorite main menu of any OS. I have the ability to change the identifier for it, search the menu, see everything grouped nicely, AND resize the menu itself. Awesome stuff.
* screenshot of Cardapio: http://i.min.us/i9sRs.png
I'm using Faenza icons:
Note, there is a conflict caused by Faenza's author overwriting PNGs in /usr/share/dockmanager which is used by the Docky DEB. I used DPKG and --force-overwrite to get them to install properly. A bit of a pain when there are updates, but really it's only one command and it's well worth it.
(The only other thing I could add is, I use dockbarx when I remote in because it doesn't require compositing where Docky does. When I do that, my setup looks like this: http://i.min.us/iErSa.png)
What would you consider a beautiful app? Chrome is the prettiest piece of desktop software I use, but I don't have a whole lot to compare it to.
That's an important distinction to make. Beautiful is not the same thing as UI. Many many people see something pretty and think that it therefore has great UI.
However UI is more than the colours (though that's important), it's things like discoverability, predicatability, etc.