EMDs can give you a small SEO nudge, but you can get just as much of a nudge by using an exact match subdirectory or subdomain.
As far as that little SEO nudge goes, the search engines only pay attention to the part of your URL that directly applies to the page in question.
So your home page may not get that little nudge, but your post pages will if you title them right.

Honestly, if .com/.net/.org are all taken, I always look for a different domain. I find that anything else doesn't get the EMD bonus.

http://www.warriorforum.com/adsense-...ml#post4242583

If the emd isnt available for net org or com I usually add a word to the end. Some add a word to the front and the end. I'm usually still able to rank high eventually. Search for best cordless drills to see an entire page of examples.