Visual Studio 2008 Beta 2
If you've been sitting on the sidelines regarding Visual Studio 2008 so far, now might be a good time to give it a look. Beta 2 has been pretty stable on my test box and there are PLENTY of new things to check out. Some of the new things in VSTO 3.0 include a visual ribbon designer, a new deployment model (I still have more investigation to do on this one), a visual Outlook form region designer, Word content control support (including data binding), SharePoint workflow support (super easy to put together basic custom workflows), a VBA/VSTO integration feature, and application add-in AND document level application support for Office 2007 (rather than just application add-in level support).
Outside of VSTO 3.0, there are lots of other things too. I'm currently intrigrued with LINQ these days. LINQ stands for Language Integrated Query. LINQ allows you to write SQL like queries against not only external datasources, but in-memory objects as well. You can write queries against any IEnumerable-based data source. SQL like is a key statement though as it is not the same as SQL. Anyway, here are a couple of good places to start learning about LINQ: