Start moving your servers to Windows Server 64-bit where possible because the next version of Windows Server 2008 namely “R2” will only be released in a 64-bit version.
One of the main advantage is better memory utilisation and limit i.e.Windows Server Standard Edition 32-bit is limited to only 4 GB memory however Standard Edition 64-bit has a 32 GB memory limit (specifications here). Now most servers these days come with more than 4GB of memory however the cost difference between Standard and Enterprises edition is a noticeable saving.
I have know about “R2 64-bit only” after reading this post on the Windows Server Blog and have been persuading clients to go 64-bit. Domain controllers are ideal candidates. Depending on the size of your organisation and AD database, the entire database can run from memory. Also most 32-bit applications will run on 64-bit Windows thanks to the Windows on Windows or WOW64. For more information read the Best Practices for WOW64 document.
The pennies finally dropped after reading Brian Madden’s blog today. Thanks Brian I agree with you “h*** sh**”