First of all you need to make 2 SCV's then start a barracks, and make another SCV. Then once you get 100 minerals build a supply depot and then 2 more SCV's. By then the depot and barracks should be done. Then make a marine and have a SCV make a bunker next to your Comand Center. Once the marine is done put him into the bunker ( you may be able to get 2 marines in depending on the speed of your opponent). At about this time a ling rush will occur. When the lings come in, surround the bunker with your SCVs and have them repair the bunker. They will keep repaing the bunker while the marine shoots and kills the lings. Then you can go from there. I think that if you can set this up quick enough you will agree that it is the best ling defense against lings. Remember not to be intimidated to attack the lings with your scv's! You might evan try poping a scv in the bunker then poping it out to repair when it needs it! After this you gain about 10-40 secs on your opponent so get more units and strucures and get your war machine cracking!

CreepColony's Opinion: Now that the 1.08 patch changed the spawning pool cost to 200 minerals, you can probably stop zergling rushes pretty easily!