although you can cut and boost up to 12 db's of frequency with the L3 I would say its use is more as a wide and multiband limiter rather than a eq.
I don't think I would use it just for Eq.
there are many Eq's for directx/vst out there and I've tested most of them it depends the type of sound you're after
algorithmix, they are rated very highly
waves linear are also particulary good
ones i tried and liked
JMS hi resoution Eq
URS eq bundle
Steinberg Q metric ( an oldy but a goody)
ones i tried and didn't like
PSP Master Q
of course that just my opinion im sure there are other people that would say the opposite its really personal choice and what you want