Timesplitters 2 *easily*. Not only is it more like Goldeneye and Perfect Dark than Nightfire could ever dream of, it features much better levels and gameplay. It's just plain FUN. On top of that, you have the incredible multiplayer (easily the best in an FPS yet, if you ask me, besides UT). It has so many gameplay modes, stages, characters, and weapons it boggles the mind. Gonig even further you have the map maker included, which is a great bonus (I haven't experimented with it too much, but my friend makes maps all the time).
Seriously, if you enjoyed Goldeneye or Perfect Dark a all, get Timesplitters 2. Not saying that Nightfire is bad, just that it's nowhere near as good as Timesplitters 2.