Aye, 3rd gen figures still figure in my work - I have some great products for them and they do have their own look and that adds variety in my runtime. Like others, I'm not sure what I would buy for them now and that is also a point that I have reached with the 4th gen figures.

If I had a 3rd gen wish list, it would be weight mapping / joint corrections, and a new set of expression morphs - as WandW mentions, these are the biggest weekness in these figures. Expression can make or break an image for me and I remember how much I loved Miki and Koji just for what they could do that way (Mankahoo's figures are also great in this regard). I remember that there were a couple of extra replacement heads for V3 (I have them both) that  have some great expression morphs that were worth the purchase alone.