At one time, I built medium satellites with heavy PPB V's and a combat sensor. A dozen or so of these satellites were pretty effective against stuff coming through the wormholes.
Nowadays, I'm too lazy to lay mines *or* satellites. Instead, I just build tons of fighters which I can launch from the planet and then move to the wormhole the next turn. I've found that 200-400 small fighters does a pretty good job of discouraging the enemy from sending ships my way.
Forgot... In my current game, I switched the #1 player to human control to see how he was doing. Lots and lots of cloaked dreadnoughts with Cloaking Device 3. I just declared war on him. Hope they come my way. I haven't researched scanners yet...
[This message has been edited by raynor (edited 05 March 2001).]