Well it is short, unique and somewhat phonetical. I'd give it a B.
http://www.skrenta.com/2008/01/about_the_name_blekko.html
If we succeed, the name will be considered great. If we fail, people will blame the name. Does the name really affect anything? I bet good results are more important.
I'm of the opinion that if you don't have creative enough people on your team to come up with a good name you probably have bigger problems than the lack of a creative name.
Note: I'm a fan, and hope you guys kick ass -- I'm just being honest with my opinion.