<p>I'm working on a visual studio 2005 vb.net windows forms project that's been around for several years.  It's full of default textboxes, labels, dropdowns, datagrids, datetime pickers -- all the standard stuff.  The end result is a very gray, old-looking project.</p>

<p>What would be the best approach to making this project look fresh and snazzy?  I'd rather not rewrite the entire solution with all brand new forms objects, but would that be avoidable?</p>

This depends on how the existing "gray old looking" project is structured in terms of code.  For example, is data access code separated from the UI in a Data Access Layer, is the business logic in a Business Logic Layer?  If yes, then cleaning the UI for a snazzy look should be relatively simple.
If everything is all there in the "Button Click" event, then a rewrite is the only way in my humble opinion as otherwise it will just be too time consuming trying to work with the existing code base.
Cheers