Ubuntu: tweaking GNOME

Recently I switched to GNOME desktop environment (don't know yet for how long). In XFCE4 I liked very much xfce-smooth theme, so I installed the package gtk2-engines-xfce and its dependencies.
What I disliked in GNOME, that the icons sizes in main menu and toolbars were slightly bigger than I would like. After some googling I came up with this ~/.gtkrc-2.0 file (with some comments from me):

#gtk-icon-sizes="gtk-menu=48,48:gtk-button=48,48:gtk-small-toolbar=48,48:
gtk-large-toolbar=48,48:gtk-dnd=48,48:gtk-dialog=48,48:panel-menu=48,48"

#gtk-icon-sizes="gtk-menu=48,48" #changes icon sizes in menus: file, edit, etc.

#gtk-icon-sizes="gtk-button=48,48" #changes icon sizes on yes, no, delete, cancel,
                                   #back, forward, etc. buttons

#gtk-icon-sizes="gtk-small-toolbar=48,48" #not sure about this

#gtk-icon-sizes="gtk-large-toolbar=48,48" #changes icon size in toolbars (don't know
                                          #why it's 'large'). also changed gaim icon
                                          #size in notification area (system tray)
                                          #default size on my setup was 24,24

#gtk-icon-sizes="gtk-dnd=48,48" #don't know

#gtk-icon-sizes="gtk-dialog=48,48" #don't know

#gtk-icon-sizes="panel-menu=72,72" #changes icon size in so called 'start' menu
                                   #(ussualy it sits in lower or upper left corner)
                                   #default size on my setup was 24,24

gtk-icon-sizes="panel-menu=16,16:gtk-large-toolbar=20,20"

http://gnome-hacks.web.com/hacks.html?id=43
http://gnomesupport.org/forums/viewtopic.php?t=11297
http://www.ubuntuforums.org/showthread.php?t=51640