I’m happy to report that I can now complete the trilogy of posts on browser font rendering on an upbeat note. After complaining about Firefox’s font rendering on my Ubuntu Linux machine, and the magical disappearance of fattened-up fonts in Flock, I’ve finally found the solution. And no, it’s not buying a Mac… Sorry Earl. 
It turns out that a tweak to the advanced settings of the font rendering (not the smoothing but the hinting) has made things much more consistent and much more pleasing for me.
Here’s the Gnome Appearance Properties dialog box. Inside of which I hit the “Details” button. Note that once you mess with the detailed settings, all four radio buttons under font rendering are selected.. weird, but tolerable:
Then inside the font rendering dialog box, I leave the smoothing at Subpixel, but change from Full hinting to Slight. And that’s it!
So here are before and after snippets from Firefox 3 Beta 3:
And because the fonts in Firefox are now much more to my tastes, I am thinking of moving myself back from Flock to Firefox. I like Flock, but it seems to be taking a lot longer to start up than FF3. And the only “social” aspect of Flock I’ve really ended up using is the blogging tool anyway. And in fact, the ScribeFire plugin for FF might actually be nicer.
Huh.
I gave up on Flock the other day too — I felt like the performance kind of sucked and didn’t really use any of the features.
Thank you very much Richard! This little tweak makes a HUGE difference on how much nicer my fonts look on Gutsy in the entire OS and not just firefox. I didn’t realize how much nicer the whole OS can look thanks to this.