Same boat here as well.
Last year I rebuilt one of the packs for my old 14.4V drill with the cheapest NiCd's I could find on ebay and it only cost me about $20. It works reasonably well, though it probably lacks just a little bit of grunt compared to the originals. Overall I think it was worth doing.
Now however I've got a 24 volt GMC drill with both packs pretty much out for the count. NiCd prices have gone up and I can't see any way of rebuilding for less than about $45 per pack, with even the very cheapest ebay cells, (and considerably more if I want premium cells).
Honestly I just can't see the point of spending too much money on rebuilding old NiCd stuff when for not much more I can get a very decent new 18V (20Vmax) Li-Ion drill with two new packs. I'm the sort of guy who likes to fix old stuff and keep things going, so this really pains me, but I've pretty much come to the conclusion that the most economically rational thing to do is to throw it in the garbage and buy new. And the drill itself is basically in as good as new condition. Sob sob.
