Darkest Hour 4.0 was released this week. It includes some cool new maps and a reworked classic, Dog Green. The video came out a bit long but the Americans get of the beach at about 50% into the video. This was with 50 players on the 29th infantry server.
RO and DH have been around for quite a bit but imo they are still the most fun war FPS because the balance between gameplay and realism is perfect. Also the developers keep coming with great updates like this latest one.
Still plenty of players play it online so check it out: