I run admin at home for two main reasons. First, since I do VB6, Web, and .NET development on my main system here, I need to have that level of access. Secondly, many games I like won't run under a non-admin user (they were apparently designed for Win9x).
At work, I have local admin access for development purposes on my desktop. I have a custom 'power user' level access on the network and to our Citrix boxes. I have admin access on some servers since I'm also an admin some of our Intranet sites.