How to make Money with your Game (pbbg)

The eternal question, how to turn this thing into a money tree.

I've got a game coming out with lots of potential, here is my plan to make money from the game. If you have tried any of the following please let me know how it has worked out for you. (And of course if you have any other ideas please shoot them out.
Some of this are summarized from posting and conversations on other sites, so I certainly can not claim these as "mine".

Background: This is an RPG game, utility management game. Let's say a user gets 1 pt every 1 min. They buy stuff and attack other players with it.

Idea 1: User can purchase more action pts/turns/ticks.
The trick with this is that in order to maintain a balanced system, when one user buys pts. All users get points. IE: You are actually bying everyone in the game an extra 500 action points.
Alternativly, you could randomly give the purchaser and 10,20 or 30 other players the same amount of points.

Idea 2: Membership
Two types of Membership, a lifetime or a monthly. While monthly is more attractive to me, lifetime is more attractive to the player.

Membership gives you additional benefits that make the game easier to play. Maybe the ability to have a custom avatar or screen. You are allowed to buy items, units or equipment that functions in the same manner as a non-member item but it has a different image.

Idea 3: Special Items
Allow users to buy items/units/equipment that does special things or have special/higher stats. I go round and round about this one, as it has the potential to devastate the game balance. But everywhere that I read says that while the players grip about this feature, they will buy these items. This also seems to be the starting point where items in your game begin to have an external real world money value.

Idea 4: Earn Refuge
Most games give refuge to new players, they can't be attacked for 24 hours. A player could by refuge and not be attacked for a given number of hours. This has the potential to mess with game balance if a player is able to buy this for extended period of times.

I'd like to hear what your thoughts are about this...