apple has never really "lowered" the price of iPods... prices have almost always been $300, $400 and $500... the capacity/accessories have gotten better. (well, at least since they've had three capacities. the first iPod was $500 with 5 GB.)
I doubt it. When there is a boost, though, it'll probably go to 60 gigs ... seeing how that's what's in the photo iPod. I suppose there's always the chance, though, that they'll always keep the photo iPod "better" than the regular iPod by making sure it always has the bigger HD ... I guess we'll find out how things go in the next revision.
If you check out the Macrumors Buyers guide, you can see that the iPod is approximately in mid-cycle. Since you really seem to want an answer, I'll chip in with a guess that we could see new iPods in early March. (Total guess.)