This was bugging me for years.  I couldn't understand why I had to source 
~/.bash_profile to get my path updated on some of my machines and not 
others.  I thought I was doing everything right.  Now I realize the 
problem was only with gnome-terminal -- there is a check-box that I wasn't 
setting correctly:

http://www.linuxquestions.org/questions/linux-general-1/do-i-put-path-in-bash_profile-or-bashrc-or-both-540288/

"You can [fix this] by opening a gnome-terminal window and going to Edit / 
Profiles - select the Default profile and click the Edit button. On the 
Title and Command tab, click the check box for Run command as a login 
shell. Your .bash_profile file should be sourced the next time you open a 
gnome-terminal."


So ... you want "export PATH=..." to be in ~/.bash_profile, not in 
~/.bash_rc, and you want gnome-terminal, if you're using it, to be 
starting as a login shell.

Mike