Unless you have been on a deserted tropical island, you would have heard about the Excel 2007 bug whereby =850*77.1 would display 100000 instead of 65535. The issue occured when displaying numbers in the ranges of 65534.99999999995 to 65535 and 65535.99999999995 to 65536. Well, it is fixed, available for download, being added to the automatic updates and bundled with Office 2007 SP1. If you need the fix now go to:

Excel 2007: http://support.microsoft.com/default.aspx/kb/943075/
Excel Services 2007: http://support.microsoft.com/default.aspx/kb/943076

Good work Excel team - now go and get some sleep! For more info, check out the Excel team blog