I much prefer working in Excel 2007 to Excel 2003. Despite the issues with backward compatibility, there are a lot of advantages and benefits to using the new version.
Some little things that have been changed are
The previous limit on nested brackets in formulas from 7 has been increased to 64. I used this today
The number of columns and rows has increased. I used this today.
I had to develop a file for a client that involved a complex work roster arrangement to calculate days off in repeating 2, 3 or 4 week cycles for the next 20 years.
Here is the nested formula that got me the logic for a roster.
I then used one formula to generate over 600,000 cells and create a map that looks like this.