Tracking/managing inventory

How do you track your available inventory? Right now I'm putting all my data into Excel spreadsheets, but they keep getting more and more complex, andI keep finding a need for more and more of them. On one sheet, where I'm also calculating unit costs, I'm tracking a total inventory of how many were made, how many were "lost" (cracked, had extrusions, taste-tested, etc.), how many were sold, and how many are still available for purchase. Today I realized that I also need to keep track of how they're packaged--individually, or in a box of 2 or 3--so that I don't, for example, promise someone 12of a particular flavor because my spreadsheet says I have that many available and thenend up having to pull them out of boxes! I also have yet to mix up flavors in boxes, and once I do that, then I really don't think my current system can handle it. I've worked with Access before, so I know it's possible to use it to track everything I want it to track, but I also have never had an easy time getting Access to do calculations for me, which is what makes me shy away from it.

So what system do you use for inventory tracking, and does it do other things as well like tracking costs and sales and so on? What do you like about it? What other features do you wish it had?