I thought Sub Command sucked hard. It placed too much emphasis on being a sonar simulator and the missions are generally uninteresting and the AI leaves much to be desired. Sid Meier's Red Storm Rising is still a much better nuke sub game despite being released 15 years earlier. And I'd like to think the Strike Fighters games have busted the myth that the cold war setting offers no good scenarios. 1970s/80s combat against the Soviets in their prime will always be superior to contemporary settings against China or whatever.

Ask, and you shall be given...

http://en.silenthunteronline.com/

although, I'm pretty sure after this you'll wish you hadn't asked.

(browser game btw)

A F2P browser online game?

This would almost be hilarious if it wasn't so sad.