Neverwinter uses a combination of two lighting systems.
a) Static Lightmaps. They're built as you load the dungeon based on the lights available. Given the reasonably uncomplex nature of the dungeons (ie not many polygons) you can built lightmaps in a very very short amount of time.
b) Dynamic Lightmaps. This is used mainly for the player, where the players lightmap dynamically interacts with the level. Stuff like that is a pig to develop, however in both cases your looking at physically dropping 5fps max even on an old TNT2 card.
The techniques rely more on processor speed, and I can easily see a Pentium III 500MHz being able to handle it without much problem. Shaders are seeming to be what people want to use, and creating one just to light the level in a very nice high-resolution way isn't much of an issue really. For Shader hardware again your looking at a small speed loss overal, but probably be something around 20fps.
Though you would be limiting yourself to who can play the game, and how quickly. Once you get into the realm of Normal Map Lighting, then your going to watch your FPS just plummet on the budget cards.
I'd say find out a game that has the level of detail your looking for and stick with it. I think Baulder's Gate Dark Alliance on the X-Box and GC does a very nice job with shaders without going overboard. It still uses lightmaps for the actual lighting but then blends them with each players accentuation light (which is a shader) Gives everything a nice bump when the player is close to it.
However given the distance these games are played at Bump Mapping over Normal let alone anything as complex as what Evo did is more than enough because players just won't notice the detail.
