I love Texas Hold 'Em, it's the most popular card game being played right now, and with it's mostly psychological focus, and less reliance on luck, I believe it will be popular for a very very long time.
With that said, I think it would both stimulate the economy and increase user bonding/interaction if an on site Texas Hold 'Em table were added. Users can bet and win/lose coins.
I doubt this will be added, but I'm on pokerstars right now and figured why not suggest it.