Win 2003 Ent Srv (32 bit), SQL 2005 Ent (64 bit)

Virtually all of todays programs are compiled in 32 bit word, so the 64 bit word processor will run 32 bit word, not 64 bit word. So you don't get 64 bit word processing performance out of your hardware if the software is compiled in 32 bit word.

If the application will be compiled in 64 bit in the future, ask if there will be an upgrade path to 64 bit.

You are using a 32 Bit OS and want to install a 64 Bit piece of software on it namely SQL 2005?

Sorry but if that's the case it will not work as the OS is unable to run 64 Bit Applications and I doubt that you'll be able to even load the 64 Bit version of SQL.

You can go with a 64 Bit OS and install both 64 & 32 Bit Programs on to the 64 Bit OS and that should work provided that you are not intending to use this as a printer Server as that may lead to problems with the necessary 64 Bit Drivers for the printers.

But other wise you need the 64 Bit OS to load the version of SQL that you want to use and this would probably also make a good base unit for Exchange 2007 as well as that is a straight 64 Bit Application that allows much more in terms of available Mail Boxes, Rules and size limits.

Col