When you just have the one wall like that sitting in a room all by itself, it doesn't really tell you which looks better.
But I think you will find that if you do the same thing with an entire scene, then having the correct lighting on everything will make the scene much more convincing than a scene where the lighting on a wall texture comes from the top even though the light is illuminating it from the side.
That said, its a lot of work to make normal maps for everything! Did HL2 have normal maps on everything? I'm not sure. If it did, I couldn't tell. Unless your art guy is a genius capable of making something as great looking as HL2 are you sure all that extra effort isn't just gonna be wasted? Personally, I wouldn't bother with normal mapping unless I was making a commercial game on a big budget. It's just silly to do stuff of that complexity for a value priced game or a shareware game being done on a small budget. Especially if the art quality isn't there to take real advantage of it.
But I think you will find that if you do the same thing with an entire scene, then having the correct lighting on everything will make the scene much more convincing than a scene where the lighting on a wall texture comes from the top even though the light is illuminating it from the side.
That said, its a lot of work to make normal maps for everything! Did HL2 have normal maps on everything? I'm not sure. If it did, I couldn't tell. Unless your art guy is a genius capable of making something as great looking as HL2 are you sure all that extra effort isn't just gonna be wasted? Personally, I wouldn't bother with normal mapping unless I was making a commercial game on a big budget. It's just silly to do stuff of that complexity for a value priced game or a shareware game being done on a small budget. Especially if the art quality isn't there to take real advantage of it.