*Shrug* I thought Oblivion was the height of crappiness.
Fallout 3 was much better than Oblivion.
That said, I don't know where Fallout NV sits. It's really fun, but as has been said before: It didn't feel like a game in and of itself, it felt like a stand-alone expansion, so I kind of lump it in with Fallout 3.
If I had to seperate them though, Fallout NV would be just Above Oblivion.
I wont put Skyrim as my #1, because it's fun, it will eat up my time until the next TES or FO game comes out, but still: It's only Great, not Excellent.
And to back up a generation since everyone is doing it anyway: Skyrim and Morrowind just hold the same place for me. I enjoy both of them equally, but neither is my favorite of all time (Though this probably marks me as a heretic

)
If forced to put them in Order then from worst to best:
-Oblivion
-Fallout NV
-Skyrim/Morrowind
-Fallout 3