W's penchant for assigning nicknames is not a bit of false populism, sadly. Perhaps symptomatic of his inability to take anything seriously or understand appropriate behavior. It goes back (at least) to his college days and his frat. It seems that it's his way of "connecting" to people. There are news mentions of the habit dating back to his time as Governor of Texas. I've worked with people like that. People like The Copy Guy. Interestingly, one of Bush's nicknames for Rove is "turd blossom".

According to news reports, most foreign leaders consider this "character trait" to be insulting.

Keepersoflists provides a counterperspective, with the top nicknames for Bush:
The Global Village Idiot
Mr. 'Strategery'
All your w are belong to us
Hail to the Thief!
Daddy's Boy
The Resident
The Shrub
The Chadmeister
Commandanter In Chieflyness
Richard Cheney (you said President, right?)
Eco Terrorist
Lord Vader
The Wimp in Chief

From whitehouse.org (the challenge is to figure out which ones they made up, and which are real...):

THE PRESIDENT: Good afternoon. Today, in the interest of desecretizing my trademark approach to political bipartisanship and international diplomacy, I have assembled a comprehensive list of the folksy, affectionate monikers I bestow on those persons of whom my advisors wish me to be aware. They are as follows: