If I had a choice to market an ecommerce site with :
1. Company name
I would choose 2. Having a keyword in your domain names helps, especially when sites link to you. But if all you are doing is buying a domain name with a keyword, and thinking it would work miracles, think again.
As part of a complete SEO strategy it makes sense to go with 2.
I think having the domain name be your business is a much better idea than using keywords in the domain name. You get branding and don't look like a fly-by-night website. As Mr. Tabke said, you want a Google.com instead of a <your-keyword>.com.
My domain is the name of my business also. Branded so to speak. If you get more domains with keywords in them, you will risk ticking off your competition if you dominate the serps with the extra domains.
It depends how you will use the extra domains. Link to your main site? Park them? Make them independent of each other?
Who knows how Google and Yahoo treat multiple domains? Maybe good, maybe bad. Course what is good this week usually turns out bad next week. Seems the webmaster is usually the last to know!
The only advantage I know for having keyword domain is the backlinks. We were not ranking for our keywords because they were not in our URL, but then I simply asked people to link to us like this: Keyword1 Keyword2 at MyCompanyName.com
When people linked to us like that, we showed up number one for our keywords and got to keep MyCompanyName.com.
Sites that are Blue-Widgetes.com kinda give me a cheesey opinion. Maybe Blue-Widgets-World is a slight improvement... orr.. yeah, webmasterworld... hehe.