At Balance Interactive, I work with many clients who try to “keep things simple” and use their domain registrar also for website hosting. This is not a good idea.
It is best to use services for THE thing they are best at. Use a domain registrar to register your domain; use a web hosting company to host your website. While every company wants to claim they can do it all, we need to be savvy online consumers just as we are for offline needs.
Here is a great article on choosing the best provider for these needs: http://www.pubcom.com/newsletter/2009_08-15.html
And, for those of you who are thinking about hosting your own website, here is some additional good material from Toni Ellison, a colleague at Balance: http://balancegroup.us/blog/?p=233