I think that imagery having to do with traditional green table felt would be great. I think that a full-on table background would be too gaudy, but it might be possible to do something that suggests felt for the main column, with a rail for the edges.
As far as logos... hmm. The O in poker could be a chip, or the spine of the P could be a stack of chips. Just please no dice chips. I think a stack of red chips as the spine would actually look really cool.
We are also a site on the Stack Exchange network, and both the Stack Exchange and Stack Overflow logos are suggestive of stacks... We could work them into a poker theme fairly easily (chips or cards are both stacked in poker). I think we need to figure out what the "brand" of the site can be. Something better than Poker / poker.stackexchange.com. Again, playing off the stack brand could help, though I think we should avoid Stack Poker type names, since we wouldn't want to be confused with Stock Poker.