Which is the best macro lens?

[Ran_photography]

I was just wondering what many of you think is the best macro lense out there? What is the best accesories to creating great macros? What exactly to extenstion tubes do? What kind of flash and flash accesories are recomended?
Can anybody help me on these subjects?
(sorry for posting twice)

[Attic]

Take a look at the stickys at the top of the list and you should get a good idea as to what people are using.

[Action_Man]

Read the sticky thread at the top of this forum ;) ...