I've watched a couple of "Alien"-type movies recently, and it occurred to me how the popular image of an alien has dictated how we envision aliens to look like.
So, I was thinking that using our common sense we could hypothesise about what they would
actually look like, ignoring everything Hollywood came up with (mostly because Tormod said we need something new and fun to talk about!

)
So - firstly, I should state what I believe:
1) We have incredibly weird animals and plants on this planet.
2) Animals and plants evolve to fill niches. The specific demands of these niches dictate what the animal/plant would look like.
3) I think life would come up with roughly similar solutions for similar problems on similar planets.
4) I think that given two possible solutions for a specific problem, life would tend to go with the least complex, most energy-efficient solution.
So - I'm sure there's a lot more to add to the above, but let's begin: