I have been using many different Internet browsers throughout the years and based on my experience one of the fastest ones is Google Chrome. So far didn't have any issues with it in terms of speed. Another one that I would highly suggest mainly because it is very popular one and there are a lot of SEO plugins (if you are Internet Marketer) is Firefox. However, I have been having a lot of issues with it lately in terms of delay and bugs.
Also, if speed is what concerns you the most, under no circumstances use Internet Explorer.