But really, Linux is far from ugly and can look as nice as anything you can do on windows/mac. Your fonts will be the same and you are by no means limited to Gnome or any of its themes. Having bad defaults is one thing, being ugly is another.
Reddit's search is broken now but users their post some absolutely gorgeous desktops where they do all kinds of neat stuff with conky. I will try to post some if the search comes back within the edit timeframe.
Your solution has to come in some form of contribution, and it has to be specific. The best thing would be artwork, code, etc. Even if all you can do is E-mail somebody who actually works on Ubuntu, and let them know what you'd rather have, I think that would help, too.
What's "gigantic"? What's "ugly"? This would tell me nothing about how to make you happy. How about you tell them, "the text in this area here, in this particular program, is bigger than I'd like; and over here, in this program, I think having green would be better than brown". That kind of thing.
The UI is the API that users work with. Inconsistencies are frustrating.
I do agree that if you complain you also need to come with a solution and a contribution of some sort. You might what to create your own Gnome theme and show the world how it should be done. If the rest of the world agrees with you your theme will be the number one downloaded theme on http://art.gnome.org in no time.
There's more than two options out there. What about other Linux distros? What about BSD? If you're looking for something that's pretty, there's still no going past OS X, IMO.
To me, the choice is not Ubuntu vs. Windows, it's Unix/Unix-like vs Windows and Unix/Unix-like wins.
I bet there is a market for a $25-50 Linux distribution with Open Office configured to use Ms-Office formats by default, have support for all "royalties required" formats, Microsoft fonts, and have a windows/mac look-alike theme installed by default.
With Google's ChroneOS on the way and Apple's eventual move to the cloud, I hope that I can soon access my iTunes functionality from a browser. And adobe has committed to moving all of their products to the browser, so I'm not too worried about i, just wish the process would move along a bit faster.