Some NAT configurations seems to fail silently with the Nvidia downloads. When I get a chance to study tcpdump output, I'll have a few more answers.
Aside: I'm using 1.0-2960 myself since 1.0-3123 is very unstable on my system.
* Debian Sid (gcc "2.95.4", XFree86 4.2.1-3)
* nVidia Corporation NV20 [GeForce3 Ti200] (rev a3) (VISIONTEK)
* VT82C598/694x [Apollo MVP3/Pro133x AGP]
"very unstable" -> random X crashes w/ 1.0-3123. However, 1.0-2960 is considerably more stable.