Updates

2010	Multithreaded calculations when using multi-processor or dual-core chips.
	This feature enables Excel to identify formulas that can be calculated concurrently, and then runs those formulas on multiple processors simultaneously. When Excel loads a workbook it asks the operating system how many processors are available.
2007	Structured References
	Easy referring to tables and named ranges (structured referencing) within formulas and functions
	Formulas can now also include references to named ranges and table names
	The ability to incorporate structured references:
	1) reference a table (or part of) by using the name

	The maximum number of operands in a formula has been increased from 40 to 1,024.
	The maximum length of a formula has been increased from 1,024 to 8,192 characters.
	The number of cell references you can have in a particular cell has been increased from 8,000 to unlimited.
	Formulas can now be nested up to 64 levels instead of a maximum of 7.
	Can now contain structured references making it easier to work with tables or just portions of data.

	MEMORY MANAGEMENT
	This has been increased from 1GB in 2003 to 2 GB in 2007.

	RESIZEABLE FORMULA BAR
	The formula bar has its own dedicated space that never overlaps with the cells.
	A resizable formula bar now prevents long, complex formulae from spilling over and obstructing some of your worksheet.
	Resizable formula bar to accommodate long formulas.
	You can quickly resize by dragging the resize bar at the bottom, or by clicking the auto expand/collapse button at the far right.
	There is also a keyboard shortcut to toggle between the collapsed (1 line) and expanded state.

	FORMULA AUTOCOMPLETE
	Context based formula autocomplete
	In addition to cell references Excel now provides structured references that reference named ranges and tables.
	Excel functions - this includes all functions in the Excel library
	User defined functions - Functions defined by the user either through VBA, automation add-ins, or .XLL's show up as functions
	Defined Names - All defined names are surfaced
	Enumerated Arguments - Some enumerated arguments (like the function_num argument in the example) will have auto complete support
	Table Structure References - More on this in post coming soon about improved table support.

	MULTITHREADING
	Multi-threaded support for dual processors
	Multithreaded Calculations (MTC) makes it possible for Excel 2007 to automatically divide formula evaluation and computational tasks into multiple calculation engines that are distributed among multiple processors
	This arrangement reduces the time it is required to calculate workbook models because multiple calculations can be performed simultaneously.
	MTC is turned on by default and it is set to create as many calculation engines as there are processors on the computer.
	You can manually specify the number of calculation engines that Excel creates regardless of how many processors are on the computer.

	CALCULATION
	Calculations and formulas should be faster because Excel 2007 supports multi processors and multi-threaded chipsets.
	Indicates the number of processes when updating

	INCREASED PERFORMANCE
	Excel 2007 now supports dual processors and multithreaded chipsets.
	LENGTH OF FORMULAS
	2003 limit - 1024 characters
	2007 limit - 8000 characters

	The maximum number of nested functions increased from 7 to 64
	The maximum length of a formula increased from 1,000 characters to 8,000 characters
	The maximum number of characters that may be updated in a non-resident external workbook reference increased from 255 to 32,000

	The number of cells that may depend on a single area before Excel must do a full calculation instead of a partial calculation (because it can no longer track the dependencies required to do a partial calculation increased from 8,000 to no limit

	The number of different areas in a sheet that may have dependencies before Excel must do a full calculation instead of a partial calculation (because it can no longer track the dependencies required to do a partial calculation increased from 64,000 to no limit

	LINKS
	If a workbook is referenced by other workbooks you should upgrade all of the related workbooks at the same time.
	If a user who is using an earlier version of Excel opens a workbook that references a workbook saved in the new XML format, the references will not update by using the Update Links feature.
	Earlier versions of Excel cannot update links to workbooks saved in the new XML format.
	There are no modal prompts asking if you want to refresh on open and periodic refresh
	You will see a trust bar, this will display the enable/disable options
	Placing a workbook in a trusted location enables the workbook to automatically refresh without the prompt.