<p>Is VBA going to go away any time soon, like VB6 has?  Should I not develop new Office applications with VBA?  Or should I be developing all new Office Apps with VSTO?</p>

<p>Update:  Recently read this <a href="http://visualbasic.about.com/b/2009/09/26/visual-basic-and-office-an-update.htm" rel="nofollow noreferrer">article</a>.</p>

Office VSTO offers a great deal of additional functionality over Office VBA, and while I don't believe Microsoft has signaled that it's going to terminate VBA (in fact,
they've said explicitly
that it will be around at least until Office 14; Office 2007 = Office 12), I think it's well worth the effort to move your applications to VSTO to take advantage of the additional flexibility and power.
I actually don't think that deprecating VBA would be feasible, since a fair amount of Office programming takes place at the macro level by business users and I don't think that's going to go away any time soon.  Those folks don't generally have access to a VSTO-capable IDE.