I just realized that this game hasn't been mentioned, but does anyone currently play it? It's browser based (unfortunately) but it's really nothing like a normal browser based game. Basically it starts with a wholly historically inaccurate map of WW1, with every country starting out equal risk-style, where each country is taken by a player and things go from there.
Personally I find it to be a lot like diplomacy except without being playable in one session. Generally things take a while, I think rounds take a month (though I haven't personally completed one yet as I'm still on my first), so it has that touch of making you think about strategies when you're not even playing it.
It has a sweet intelligence system where you can do anything from delaying production of that tank or intercepting a message between your enemy and your ally giving away your military locations.
The combat system is generally a case of 1 v 1 meaning everyone suffers high casualties, with top tier forts making the attacker need something like 4 to 1 odds to be equal, so it's often based on outmaneuvering your enemy, making fake attacks, or just throwing troops at your enemy knowing half will die. There are things like artillery and railguns to bombard your enemy from afar and battleships to intercept enemy troop transports and so on.
Economically there are a bunch of different resources, which you have to juggle around and often trade on the stock market since you're probably not a self sufficient country. Each province produces a single resource, with some provinces producing twice as much and thus being more valuable and sought after. Additionally, you start building factories (to produce tanks and artillery) and railways (to increase production and movement speed) a few days into the game.
Overall it's very complex and has this kind of Hearts of Iron+Diplomacy+Risk feel to me with all the best parts thrown together, though I'm not saying it's the best thing ever and it's probably not for everyone.
Edit: Oh, link
http://www.supremacy1914.com