I recently mentioned conditional formatting as perhaps the Excel functionality I've most increased my use of it in pricing tools. The second-most functionality would be named ranges, especially on more complex tools. Most Excel users want to be able to self-diagnose what's going on in a formula when it's not giving the result they expect. The less they have to bounce around the file, the faster they can do this and the fewer times they have to ask around for help.
What's easier to diagnose- "=$B$176*Input!A32", or "num_Sites*num_Months_Startup"? Extrapolate that against a complex formula reading 4 difference scenarios, and you get the point.
