My friend Lee has a good post on performance monitoring for SQL server on his blog: http://www.texastoo.com/post/2009/06/18/How-to-quickly-assess-SQL-Server-performance.aspx
My only comment is that including “Disk Queue Length” is also a good practice. If you start seeing queues build on your drives it means they’re being overloaded and you need additional channels. I’m not sure of a specific number to watch for, but I would think anything bigger than 1 deserves investigation.
On Server 2008 setting up perfmon is a snap, use the wizard. Once you have a data collection set created give it a schedule so that it can run regularly so you can track performance trends over time.