This image should at least be posted once in every "but it's possible for someone to create the same address, right?"-thread:
*snipped image*
The image says 2^256 though
Isn't it just 2^160 for BTC?
2^160 addresses, right. Private keys, no, that's
almost 2^256.
No use generating an address if you don't have the private key to it

It is more likely that the Earth is destroyed in the next 5 seconds, than that a collision occur in the next millenium.