The Inheritance Playthrough
Definitely my favorite Someguy2000 mod, as I've never been that in to New Vegas Bounties; at least as something you could sit down and play through as a one-shot experience.
With all the gritty cowboys, military men, and bounty hunters in New Vegas mods, I honestly feel like there's not enough done with the Vegas City Slicker Wise Guy thing in the general population of mods, so The Syndicate is a refreshing change of pace.