I've decided to delve more into fully unit-tested code and write an application from scratch using TDD methodologies after being re-invigorated by Robert C. Martin's fantastic Craftsman article series ( http://www.objectmentor.com/resources/publishedArticles.html -- click on the "Test Driven Development" category).
I'm using NUnit ( http://www.nunit.org/index.php ) to do unit tests, with TestDriven.NET ( http://www.testdriven.net/quickstart.aspx ) used along with an obsolete version of NCover ( http://www.ncover.com ).
I have no complaints with NUnit, but TestDriven.NET has some strangeness in studio 2008 that I will detail shortly, once I make sure the issues that I am facing are not simply due to PEBKAC on my part. NCover seems quite nice to be able to have a way to see NUnit coverage, without resorting to the MS tools (which do not seem to play nicely with external testing frameworks like NUnit).
Try new version of NCover and review it (the version I have now does not seem to respect the setup and teardown attributes before running tests)
Complete first release of FileCombiner (I'd estimate the initial features are at about 85%, with ~85% code coverage according to NCover)
Publish release, with unit tests.
Beautify the UI; use WPF, include progress bar and diminish use of textbox as a vehicle for reporting progress