Best life link magic cards

There are two things you might see in magic which are related: lifelink and "When this creature deals damage, you gain that much life." They both do exactly the same thing, with one difference. A creature can only have lifelink once. Lets say you have a creature with lifelink and you put the enchantment "lifelink" on it. Nothing happens. However, if you attach an enchantment that says, "When this creature deals damage, you gain that much life", then you'll gain life from the creature's lifelink AND the enchantment effect.

As far as figuring out how much life you gain: your creature deals damage equal to it's power. If your killing a 1/1 with a 10/10, you still do 10 damage, and gain 10 life. If your killing a player who has 1 life, you still gain life equal to your creature's power. If the damage is prevented, then you don't gain life. If your creature has double strike, picture it as two distinct strikes. The first one deals damage, and if it doesn't kill the creature, then your second one hits. In other Words, if you have a 10/10 with double strike and lifelink being blocked by a 1/1, you gain 10 life, not 20, because the second strike never deals damage.