On the topic of domain names, I suggest starting your site with any domain name as long as it's easy to:
1. Say (think on a phone message or in a loud networking room)
2. Understand for the person listening
Then, work towards getting a domain name that's easy to:
4. Remember (this is less important immediately, with emails/ bookmarking, but this one can't hurt)
I also don't recommend getting a domain name with dashes if you don't own the un-dashed version (from personal experience).
Keep in mind that you can always get more domain names and forward your site, once finished to them. You can test many domain names in this way. Don't sit on starting the site for the sake of getting the "right" domain name.