I make my money by selling items, so it would be really useful to see which items are selling and which aren't. Being able to see what is happening to item sales over time would be great. I can imagine a graph or a report that shows the number of items sold (per month, per week, per quarter, per year) for a selected period of time (year, month, quarter) and maybe to compare to previous years/months/quarters.
For example if I've had to put my prices up and that has impacted on sales of certain items it would be so easy to see if item sales could be tracked over time. In fact any account shown over time (like a detailed profit/loss by account) is useful, so same could be said of items.
"Item sales tracking"