No doubt about the CM 690... Far better than the Antec 300...and comparative to the 900 in terms of features but is about $30 cheaper... So CM 690 without doubt...
I think I'm going to get the CM 690
I would go with either Antec Nine Hundred Two or wait for CM Storm Scout to be released. The Scout looks like it is going to be an outstandring mid-tower gaming case, which is designed for LAN party usage as well.
I built half a dozen pc's for other people using the Coolermaster 590 case. It's a good case for a general purpose build. Space will be tight for a gaming case. The Coolermaster 690 is better for gaming because there is more room for large components.
The Antec 900 is a very popular case with gamers. I have not seen actual sales figures but from what I've read, it's probably one of the most popular cases available. The Antec 900 II is a new and improved version of the case.