Tracy, we went through this in 2002 and ended up doing quite a lot of UI stuff in C#.
One issue that nobody has raised: spend at least some time checking the market for shrinkwrap that offers functionality for a fraction of the price of development. If it is a corporate app, there *will* be functionality out there that could save you a fortune or make development decisions a no-brainer. Example- I know one developer who modified a commercial store-front app for a total cost of $50,000 when consultants were quoting $500,000 for an exciting write-from-scratch.
Are you able to provide a sketch of what the app needs to do?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
