So I've chosen a font by
System Settings -> Application Appearance -> Fonts
And there I've adjusted all fonts to be of 14th size. And also checked "Use my KDE fonts..." in Gtk+ appearance. I've also did the same using
kdesudo systemsettings
But still some fonts are tiny! It's not the 14th size!

Edit 2:
I thought it might be one of Gnome font settings. So I've increased all fonts in
gnome-tweak-tool
sudo gnome-tweak-tool
gconf-editor
sudo gconf-editor
No help!
Edit:
Ubuntu tweak also gives no help (note the tiny fonts!):

Edit:
It looks like the problem is with gtk3: when I compile emacs 24.0.92 with gtk3 - i get small menu fonts. When I do the same with a default gtk2 - everything is all right.
xrandrshows it's incorrectly detecting display size, you can forcibly change it to the correct size wiki.ubuntu.com/X/Config/… – maco Nov 7 '11 at 18:431600x900 59.9*+. The problem is still around. – Adobe Nov 8 '11 at 7:06ubuntu-tweakdoesn't change a signle font for me - nor doessudo ubuntu-tweak. – Adobe Dec 9 '11 at 16:27