I am in the process of building a new machine used primarily for web and
Windows Server applications. Visual Studio, SQL Server, remote
connectivity, monitoring, etc. Would you consider Vista reliable and
dependable enough to use as a primary OS?
If you are developing for the Windows platform then, yes - Vista is
reliable.
For Visual Studio 2005, make sure you apply both Service Pack 1:
http://www.microsoft.com/downloads/details.aspx?FamilyId=BB4A75AB-E2D4-4C96-B39D-37BAF6B5B1DC
... and the SP1 Update for Vista:
http://go.microsoft.com/?linkid=6366078
If you are using the Visual Studio 2008 Beta, it runs "as is" on Vista.
For SQL Server 2005, you need to apply Service Pack 2:
http://go.microsoft.com/fwlink/?LinkId=77674
More fine print about SQL Server on Vista, here:
http://www.microsoft.com/sql/howtobuy/windowsvistasupport.mspx
To test your projects on Windows Server 2003 or 2008, you may want a Virtual
Machine environment running on Vista. Virtual PC is free and is supported on
Vista Business, Enterprise and Ultimate editions:
Virtual PC 2007
http://www.microsoft.com/windows/products/winfamily/virtualpc/default.mspx
While not strictly required for development on Vista, you may want to
install Network Monitor 3.1:
Microsoft Network Monitor 3.1
http://www.microsoft.com/downloads/...9D-F4D8-4213-8D17-2F6DDE7D7AAC&displaylang=en
NetMon is invaluable for understanding the behaviour of distributed and web
applications (especially when the "behaviour" is misbehaving

Version 3.1
is fully Vista-compatible.
Hope it helps,