Xrysthos said:
and maybe 1 in 3 galaxies contains a planet suitable for life.
I'm not sure you took the same science classes that I did....
Sorry, couldn't resist
Anyway, to the OP, I feel the same way about extra terrestrial life. I can't remember which one, but in one of Richard Dawkins' books he attempts to give a probability for life evolving on Earth within our timeframe. He uses the least probable numbers avalible to him, and then compares it to the (estimated) number of planets in our galaxy. Assuming that any planet is as likely as another to support life (i.e. Venus or Pluto are as likely to have "Life, Jim, but not as we know it" - apologies to trekkies if I got the quote wrong - ) then the estimated number of planets with life was something like 3000, mabey 300.
As for the physical properties of this life, given that we have a full periodic table and that every phenominon we can detect uses a standard set of atoms or derivatives thereof (ions, isotopes) I think it is a fairly safe bet that such a set of 'building blocks' is consistant across our galaxy and indeed the universe. Any other life would have to be capable of replicating itself on a molecular chemistry level before evolving to higher life, so i think it would have to have a structure based around a 'code' such as DNA, but I believe the chances that the molecular structure of this 'code', the psycical structure of the aliens cell and tissue equivelent and the aliens' shape will be very different to humans'.
Whether we will ever be able to communicate with any aliens we meet is another story, however given the amount of ways a modern science lab can send and recieve energy I think we have at least a chance. An interesting side note would be if Mass Effect had a point with the "Cypher", I'm no linguist but it's possible that there is a shared, cultural ability to understand language, and we wouldn't have to particular "Cypher" of this species. We will only have to wait, and hope to one day be able to see.