I've been conservative with Vampire: The Masquerade - Bloodlines. The only modding I do is boshing on ye olde unofficial patch, without even enabling the optional new bits, and maybe replacing my character model with a nicer NPC model. I might be bolder next playthrough, as apparently we're spoilt for choice with Bloodlines mods at the moment.
Mega-expand-o-overhaul Bloodlines Antitribu [official site] came out last week, with oodles of new clans, models, levels, weapons, skills, quests, characters, and so on. A new version of big overhaul mod The Final Nights [official forum] arrived too.
Antitribu sounds pretty massive, just check out the feature list. I am pretty keen to play as Tzimisce - y'know, like the chap who made that wonderful meathouse. They can turn into horrible meat monsters and collect meat to turn into meat puppets too (though they appear to be Aliens aliens). Look at this:
You can download Antitribu over here. A later version will introduce a Sabbat main quest line too.
The Final Nights is also a big add-o-overhaul mod, based on the Camarilla Edition mod. It adds new clans, quests, voiced NPCs, game systems, and oodles more. Version 1.3 came out last week, and you can download it from this list o' mirrors. Do grab the 1.31 hotfix too.
Bloodlines is one of those games I seem to end up replaying when someone mentions it, and apparently I'm doing the mentioning this time. Tell me, gang, have you dabbled in modding Bloodlines much? Anything else you'd recommend I have a gander at?