From a utilitarian point of view, posthuman (or post-AI) beings might be able to sustain greater levels of utility than humans ever could (this is almost certain, since the space of possible minds is much bigger than the space of possible human minds). Hence the universe could be a much happier place with these beings around.  
 
But motivation-wise, of course much of current posthuman thinking is the apotheosis of the nerd. The people most interested in cognition enhancement are academics. A future with software intelligence has an obvious appeal to anybody who "gets" software.  
 
That does not tell us anything important, though. The Internet was invented for certain purposes but is now used for a lot more things. Cognition enhancers might be desired by a few cerebral people today, but once available people are going to find everyday uses of them. I think humanity will go posthuman not because most people want it, but because every step will be seen as practical and fun. We nerds will find that we will have the greatest success in spreading new technologies when they can fulfil human desires: the nerds may lead the way, but the funding will be mammal-controlled.

I managed to get an update done to my blog, which now shows the z-score correlations (old plots retained as a warning to myself and others).  
http://www.aleph.se/andart/archives/2008/09/openness_is_creative_but_does_it_earn_money.html 
 
Yes, openness now has a positive mild correlation (0.2) while all the others are negative: extroversion -0.15, agreeableness -0.32, conscientiousness -0.33 and neuroticism -0.16. That conscientiousness is so bad for GDP seems just as odd as my previous mistaken result. 
 
I think there may still be some outlier effects, for example in neuroticism. But the signs of the correlations seems to be stable.

Thanks for calling me bold. Unfortunately as Nathaniel's comment about my mistake show, that doesn't make me right. Of course it should be the z-scores!  
 
I'll correct/update my blog with this in a few hours (I have to give a lecture on cognition enhancement first - right now I really feel I need it myself).

p-ter: while swedes do have a modicum of dress sense, their egalitarian streak makes them react to symbols of status - not necessarily in a negative way, but often by clamming up or withdrawing. I noted that when I walked through Helsinki in a neat suit people treated me with noticeably more deference than in Stockholm.  
 
Using Geert Hofstede's cultural dimensions framework, one explanation could be the lower masculinity of Swedish culture (lowest in the world) and the higher Finnish uncertainty avoidance. 
http://www.geert-hofstede.com/hofstede_sweden.shtml 
http://www.geert-hofstede.com/hofstede_finland.shtml 
 
Peter: no, suits are fine. It is ties that are evil - they constrict the throat, prevent you from unbuttoning your shirt and tend to end up in the soup. The neat thing about suits is that you can take off the jacket or wear it depending on temperature (very useful in severely airconditioned countries like the US).

I can recomend John T. Molloy's _Dress for Success_. It is a relatively old book and very directed towards business types, but what makes it great reading is the experiments the author and his collaborators did to check the social impact of different clothing. Does a brown or black raincoat improve your chances of being let through a door first? What are people's reaction to suits of different colors? That approach, to deliberately look at what social signals you send with your clothes and then engineer signals that fit what you want to say, is both fun, nerdy and useful.  
 
Moving as I do between the think-tank world and the academic world it is very amusing to study the reactions to appropriate and less appropriate clothing. Wearing a suit reduces questions after a lecture to Swedish students by ~50%, wearing a tie completely abolishes questions. Conversely, you can easily scare most Swedish businessmen with your sense of style just by having something relatively cheap from Armani.  
 
Dress for Success also makes the important point that the smart businessman of course buys as much clothes as possible during the sale. I think I pay less for my formal wardrobe than many people pay for their casual clothing.