As A User
All my browsers have their home page set to Google.
I prefer Google because their home page is simple and light. MSN and others send me screaming for the hills with all the crap they stuff in your face upon landing there. If I want the news, I'll hit a news website. If I want to search, then I want to search! Get all that other stuff out of my face.
When it comes to search engines, simple is better. IMO. Results are pretty good too.
As A Webmaster
Google rocks! Especially in a startup situation. Code your site to standards, submit your site and sitemap, and update often. Google will love you forever. (And yes, bla bla... backlinks... bla...)
The other SE's... well... not so much, I've found. Seems to take more time for updates to be seen by them. (Just a personal observation) I just submit and let nature take its course with those. I don't de-value the importance of the other SE's - they're all important, but I do tend to focus my efforts on Google.