Leaving out R&D, my guess:
the GPU: approx. $70 - this based on the large die, and the fact that they don't own their own fab (overhead) and includes the package, testing, the package and package yield loss (assembled die that don't pass once packaged).
the memory: hard to guess since I don't know the FSB (150MHz? 200MHz?), but probably somewhere on the order of $40 in bulk for 64MB.
The card and the other components: probably a 6 layer PCB, plenty of caps, a heatsink & fan, resistors, other chips. my guess $18
packaging: $2
Total cost: ~$130
That's my guess, anyway. I have a feeling it's on the high side, but I'd bet money that the assembled card is over $100, and I'm sure that the bulk of the cost is in the GPU.