As one leaning toward Intelligent Design, I'd like to ask what would you consider evidence of design?
It is an excellent question and it is unfortunate that ID proponents have not done a better job of both defining what would constitute evidence and then providing it: irreducible complexity simply doesn't make the grade. Here is my list of evidence for design:
1. Things exist. We know some things have been designed, therefore the potential exists that all things might be designed, or at least that some things not currently thought to be designed might be so. (We should not forget Slartibartfast's work with fjords!) However, while this is evidence, it is not very good evidence.
2. Identifiable code within DNA equivalent to a PIN number, patent identifier, or similar. Alternatively a coded value of pi to, let's say, around 1000 places; or similar for any fundamental constant. Think Pioneer plaque writ in adenine, thymine, guanine and cytosine.
3. Genotypes that stand outside a nested hierarchy.
4. A message from an extraterrestrial source explaining that their ancestors designed us.
5. This is highly speculative as I just don't know enough about this field, but I wonder if a Bayesian analysis might be able to demonstrate that known examples of poor design were more likely to be the result of convenient (lazy) adaptation of existing sub-routines (i.e. genes) rather than chance/natural selection.
If I come up with anymore I'll post them, but I really think it is up to those promoting, or leaning towards design to come up with categories of evidence, not those who doubt it. If there were some convincing identifiers we could look for then a search would become practical.