I'd like to give a shout out to Neotokyo, one of the best HL2 mods still regularly played. The soundtrack is amazing too. Sadly it's not maintained anymore and playing tends to be done in the weekends and friday nights.

If you've ever seen Ghost in the Shell or like cyberpunk stuff and don't mind a first person shooter in a universe like that? Prepare to have a lot of fun getting your butt kicked in by veterans.

The community deserves a remake. ;-)