After emerging the new gimp-1.2.3 ebuild and unmerging the previous, there is no longer a /usr/bin/gimp. One has to type "gimp-1.2" in order to run it (/usr/bin/gimp-1.2). It's not a big deal, but it means the gimp launcher in the gnome menu is broken. Problem can be solved with a ln -s /usr/bin/gimp-1.2 /usr/bin/gimp, but not all users may be aware of this.
according to the cvs log, this should be fixed.