First, yes you should be able to continue to use the older version of FrontPage while running the newer version of Office.
As far as whether you want to, it probably depends on how you feel about FP2000 and what you currently use it for and plan on for the future.
Expression is really much more a professional tool, designed to compete directly with Adobe Dreamweaver. As such it supports a lot more of the current web standards, creates better code and gives you a lot more room to grow. It probably also means you will have a bit of a learning curve. But personally, I think that if you are at all receptive to the idea, it is a good idea to get away from using FP. The only reason to keep using FP is if you want a very simple, non-interactive web site and don't want to go any further with it than you already are (and really don't want to learn a new application).
Another thing you can do if you are trying to decide is to <a href="http://www.microsoft.com/Expression/products/overview.aspx?key=web" target="blank">download the trial version</a> and check it out for yourself.
Dale
