I have noticed an interesting trend towards larger, more power hungry video cards. Thus, the cooling solutions have also grown... so, I thought I would post a bunch of pics comparing the coolers with each subsequent generation of Nvidia cards...
Lets start at the beginning:
Nvidia Riva TNT2
No fan, small heatsink
Nvidia Geforce 256
Small HSF solution
Nvidia Geforce 2 Ti
Enter the custom cooling solution!
Nvidia Geforce 3 Ti500
Ramsinks are added
Nvidia Geforce 4 Ti4600
A more efficient design??? really???
Now begins the era of mammoth cooling solutions and supplementary power from PSU...
Geforce FX 5950 Ultra
Pulls in air from outside and blows into the case. Notice the absence of heatpipes... Either they hadn't been invented or Nvidia didn't think they were necessary. Add in auxiliary power via a 4-pin molex power connector
Geforce 6800 Ultra
<- 2 slot internal cooling solution.
See that big metal thing that goes across the memory sinks? That's called a heatpipe.
Also, 2 molex power connectors now.
Geforce 7900 GTX
Nvidia got a little happy with the heatpipes on this one. Enter the 6-pin PCI-e power connector.
Geforce 8800 GTX
Exhausts about 80% of heat out of the case. Large blower fan. 2 x PCI-e power connectors
Geforce 9800 GTX+
First solution that fully covers the entire PCB.
Geforce GTX 285
...an even larger fan than the 8800 GTX and 9800 GTX+
.... and finally...
Geforce GTX 480
Exposed heatpipes, exposed "grill" cooler, 1 x PCIe 6pin and 1 x PCIe 8pin power connector.
Geforce GTX 580 (Fermi done right!)
Similar design to GTX 480, without exposed grill cooler. Vapor chamber technology added to bottom of main heatsink. Quieter Fan.
NO HEATPIPES!!!! 
So kids, what have we learned today?
EDIT: Added GTX 580