FilipJPhry said:
the worst ones are with an atheist.
I'd change that to "the worst ones are with people who bring religion into it".
'cause seriously, Atheists and Theists are as bad as each other with all this.
OT: If we had quantum entanglement all figured out, I'd put a quantum entanglement communicator in it. Get to talk to them, and its untraceable I'm pretty sure, so we may be able to discern the aliens motives by talking to them, whilst not letting them know where we are.
However, any messages in written or spoken words will be lost in translation. I severely doubt aliens will have the same language as any on Earth, and they'll just look at it and wonder what it means, trying to decode it through scientific research or something.
Also, food and drink gifts may not be a good idea either. There is no guarantee that:
a) The food/drink will last the 1000 or so years until we find an alien
or
b) That the alien will be able to ingest the food or drink safely
Images or sounds would be Ok to send, however possibly the best thing to send would be a mathematically encoded message. Utilising cosmological constants and basic mathematic principles, we can establish a base for communication of numerous things. How to present that may be an issue, however displaying numbers and mathematical formulae involving those numbers, as well as flashes of light or simply lit up lights as a concept for them to link with the symbols we associate with numbers [I.E: 3 lights are on, and you display 3. Show a plus sign, and another three lights with 3 above it, then an equals sign, and 6 lights with a six above it. Show multiple such messages so they understand which way to read them, and can deduce what each symbol is.].
That sort of stuff may be a good idea. Once you've established mathematics, you can move onto science - likely Chemistry and Physics first, then Biology - and eventually language.