I think we were all a little dubious when we first saw someone claiming to do streaming full-resolution gaming from the cloud. I think it sounds great, but I'll believe it when I see it. But it's still in Beta, and while they technically still have time to make their "Winter 2009" launch date posted on their website, somehow I think it's gonna come and go without a finished product.
Re: Black Mesa, it's a shame that it's dragged out so long b/c I think the longer a private mod goes on the lower it's chances of reaching completion. Real life just gets in the way. I'd rather see Valve hand them some seed money (or heck, even lend them some talent) and then release it on Steam for $5. I think it'd sell like hotcakes.