If you can spring for the extra $$, I'd definitely go with the 770L. The 330L and 770L are essentially the same design but the 770L has many more conductors and will add a lot more power and weight to the music. It will also flesh out images far better where the 330L will sound rather lean by comparison.
I've owned both the 770i interconnects and 770L speaker cables for a couple years and they're definitely keepers.
I've owned both the 770i interconnects and 770L speaker cables for a couple years and they're definitely keepers.