"but finding another DNA form or a non-DNA form of life would be interesting."

You might be interested in prions. These are protein chains that can evolve, and behave rather like viruses. I have no idea whether they would be considered alive or not but I suspect that the line between what constitutes a distinct life-form and what doesn't is blurred anyway.

Spaw's right - the real trick is going to be recognising life-forms so alien to us they seem inanimate or inorganic. We've got a hell of a long way to go on this yet.