Here are the very important points.
1.SharePoint Server 2010 will be 64-bit only.
2.SharePoint Server 2010 will require 64-bit Windows Server 2008 or 64-bit Windows Server 2008 R2.
3.SharePoint Server 2010 will require 64-bit SQL Server 2008 or 64-bit SQL Server 2005.
In addition to the requirements listed above we also wanted to share with you some preliminary detail about SharePoint Server 2010 browser compatibility.
To ensure the best possible experience across multiple browsers we’re focusing our SharePoint 2010 engineering efforts on targeting standards based browsers (XHTML 1.0 compliant) including Internet Explorer 7, Internet Explorer 8 and Firefox 3.x. running on Windows Operating Systems. In addition we’re planning on an increased level of compatibility with Firefox 3.x and Safari 3.x on non-Windows Operating Systems. Due to this focus Internet Explorer 6 will not be a supported browser for SharePoint Server 2010.
