Humanoid aliens. The chances are so much against it, yet there's always a few humanoids just strolling around, nevermind the fact that Earth, the planet the form evolved on, has only ever spawned one humanoid species. Where are the squidfolk and crab people? I know they're Earth analogues too, but at least they're forms a few species have found useful.
English speaking aliens. We would be lucky to be able to communicate with aliens. It's a leap of faith assuming they even vocalize, it's more likely they would use flashing colors or scent markers. It's the one thing I hated about District 9, that alien prawn-speak was as hard to master as Spanish. The novel Solaris deals with this very well, the idea that communication with a nonhuman sentience (including God) is impossible.
Morbo being the exception to all this.
