How about list some potential games that you could go for, or have a good chance of getting, and then have people vote on which they would prefer...
Demand could be gauged in a more formal manner. Theres something to be said for surprise, which could still be done with things you throw in, but, you could also put up member polls for long range planning and negotiation. You could also setup polls for non-members to ask them what types of stuff they would like to see in totalgaming.net that would make them more interested in signing up for the subscription.