Now that I've read Alan Moore's graphic novel The League of Extraordinary Gentlemen (since having just recently received it as a gift), I can authoritatively say that it has, as suspected, absolutely nothing to do with the movie of the same title.
Except for the concept, which is a really neat concept, of gathering together a group of contemporary (to each other) literary characters. The novel limits league membership to five, with only four of these (plus a host of others) appearing in the movie.
But this league of characters also confuses me. Mina displays no vampiric tendencies whatsoever. She contributes no "gift" to the league but her womanly wiles. She is no more "gentlemanly" than the rest of them, and I fail to see the reasoning behind her membership. Nemo remains an enigma, having even less presence than in the movie.
The work teems with literary reference. It's a bit of clever fun, but this is not genius.
The artwork is rich, but not astounding. Admittedly, the graphic novel feels suitably dark. London is seedy, compared with the carnival atmosphere of the Venice film setting. Though there are visual references aplenty, the story is not moved along by pictures.
Likewise, the dialogue does not bestow meaning deeper than that already imbued by the name-dropping. I feel (unpopularly, I'm sure) the story concept would be better served by a traditional novel, or by a movie.