I never win.

Fallout 1&2...but from this two NV is obviously better.

Heh.

Personally, Fallout NV is superb in gameplay and story writing aspect than FO3. But FO3 wins in environment and atmosphere.

If you got both I'd suggest you to play FO3 first then NV.

By the way I'm on my second playthrough in NV... my first playthrough was almost complete game, all locations discovered, but only met with one ending and have not played any DLC yet. That took me 100 hours, so that means I'm gonna going to another 100 hours to complete 2nd playthrough. Whereas in FO3 I only need ~100h to completely 100% the game.

I much preferred FO3 over NV, but opinions on this subject are pretty mixed. The stories of the two are pretty much entirely independent (although obviously NV occurs a few years after FO3) so it doesn't really matter which you play first in that regard.