Judging by the current contests, Google might like non-hyphen domains just a tiny bit more!! grrrr!!!!
I have never found having 2 hyphens a problem, certainly would not back up any penalty specualtion, so you choose which one you want and google will give it a fair hearing.
I think the hyphen makes no difference. Google reads the keywords within the domain whether it's seperated by a hyphen or not.
My opinion - and it is only my opinion, is that it doesn't matter. Hyphen or no hyphen, one, two or three hyphens - it doesn't matter whether your domain name is my-keyword-here-and-here.com or if it's abc321.xyz - the important thing is that you have a worthwhile site, that the content is useful (maybe unique too, ... ) and that you have good, on-topic sites / pages linking to your site. Why should I (or Google, for that matter) worry about a domain name? The ONLY situation where a domain name becomes important is user memory - if you put yourself in the shoes of your users for a while, how are you going to remember the route back to your site? My rule is "keep it short, or keep it memorable". and don't worry about allinurl: !!! It's just my O MCS x