Then you can just switch account from the dropdown on the bar at the top, most apps remember which account you use with it, and you can even use gmail with different accounts in different tabs.
I find that solution to be quite decent. Generally, when I hit a google website it will prompt me to pick between my two different accounts. Even using googles oauth will prompt me to pick between the two accounts! Apparently, it isn't supported for some things, but I haven't come across anything yet.
Then you can just switch account from the dropdown on the bar at the top, most apps remember which account you use with it, and you can even use gmail with different accounts in different tabs.