The problem I often encounter with reforging is that I simply can't get a clear overview of which reforge does what to my stats. With Blizzard's reforge system, I have to go the trial and error route by first reforging to see the effect expressed in percentage or hard numbers, instead of rating. I also have to go on a per-item basis. This often leads me to perform reforges only to find out I'm 1 expertise short or overshot my hitcap by 1%, stuff like that. Annoying and a waste of gold.
What I'd like is an addon (or a website, tool, whatever) that lets you see the effects of reforges that you do, before you do them, across the board. I'm not looking for something that tells me what to reforge to what (I know my stat prio's), but that shows me what happens when I reforge X to Y.
What I envision is a basic 0-point template that shows you all your gear + enchant + gem stats, without any reforge. I can then add template reforges/restores per item and see the effects reflected on my stats. Once everything 'fits' so that I have all my caps sorted (not too high and not too low) etc., I can then save this information and go to the reforger and perform the actual reforges. Bonus points if the addon actually allows me to perform the required reforges/restores in a single click, but not required.
ReforgeLite, as mentioned above me, is a great addon. You choose class, specc and it will show how your stats would change if you would reforge after it's settings.