I primarily use ProMash, but I have a ton of random, poorly organized spreadsheets to calculate various things. I've been debating consolidating them into something somewhat usable. chuck_d posted a version of his brewing spreadsheet a few years ago. He clearly put a lot of effort into it. I was considering modifying that to my needs. It would be nice to have everything integrated in one place, particularly the yeast pitching rate calculation. At some point I backed out the equations for Jamil's calculator (which is what I use). It shouldn't be terribly difficult to add it to a spreadsheet, assuming I can actually find it.
What do you guys have in your spreadsheets? What do you think is missing or would be handy to have?