GoDaddy is my choice domain registrar, however their domain search engine sucks. I like a domain search engine that will allow for bulk searches and clearly lists your results in an organized manner along with optional extensions you specify. My choice domain search used to be mydomains.com However they've since updated the way they list the results and I can't stand it. What's your favorite domain search ?
I tend to use www.who.is because I like uncluttered websites. However, this doesn't have a bulk WhoIs. You could try http://www.domaintools.com/bulk-check/