In the marine world (freshwater seems to often have lower lighting levels), going by the lighting setups often seen in the tanks of other serious hobbyists, 3 wpg can just barely be considered high, and no where near very high.
I think something like this would be more like it:
1-2 WPG = slightly lower than low-low
2-3 WPG = low-medium
3-4 WPG = just slightly over medium
4-5 WPG = high
5-6 WPG and higher = very high
But, besides the point, WPG isn't really an accurate rule, becuase it fails to take into acount the actual dimensions of the tank and it wasn't intended for all the advanced lighting systems we have today. It can be used as a guide line and you won't go wrong using it, but if your getting into high and very high output flourescents, PC's and halides, your gonna have more light than nessisary, wich is a good thing for the inhabitants, but if you're on the low end of the budget like I am, you don't want to spend much more than you have to.
You should be able to figure out where you are in the 'light scale' with the above info, wether or not you've got enough or not depends on what you want to keep.