We use some really good development tools and I can highly recommend them to anyone out there building .NET smart clients.  Developer Express (www.devexpress.com) provide the best UI components that I've ever found.  Fully functional UI components that look great and also work like a dream.  I can highly recommend them.  I can also highly recommend XmlPdf (www.visualprogramming.com).  Built here in New Zealand, its a very powerful tool for building PDF documents and we use it for all of our PDF reports - some of which are fairly complicated but look great. 

Other tools I can highly recommend are Vault (www.sourcegear.com) for source control and Enterprise Architect (www.sparxsystems.com) for UML design.  EA is more than just a UML modelling tool, its a full system documentation repository.  By using EA, we are able to keep our entire project documentation including analysis, use cases, features, requirements, architecture, design, testing alive within an environment where it can be easily kept up to date and referenced.  EA keeps the source code in sync and as we work on small projects that touch multiple modules, we build sequence diagrams, class diagrams, requirement diagrams etc to document our projects.  This documentation all becomes part of the full documentation of our entire system.  What makes EA really outstanding is that it is database driven so multiple team members can even work on the same diagram at the same time. 

Finally, there's MindJet (www.mindjet.com).  MindJet is what's missing from Microsoft Office.  I often want to brainstorm thoughts or do research and it can be very difficult to keep track of a lot of information in a purely linear fashion using Word. MindJet allows you to start from the Nexus and keep adding information and easily structure and restructure as you go.