I think this is a great thread and could be a good reference tool for people. I especially like the pictures that were in HN1's thread which really put things in perspective.
My only suggestion would be that we stick with the fish which are widely available to unknowing consumers at chain stores and most LFS's like Bala Sharks, Tinfoil Barbs, SAE's, etc...
If we start getting into things like Dwarf Gouramis, Mollies and Neon Tetras...this might be an never-ending list which would become cluttered and hard for the newbies to take in all the information.
In that format we might as well add everything from GBR's (which die off for unknown reasons), Guppys (which many novices might not understand how prolifically they breed), Oto's (which have a substantial die off rate when new), etc...
Again, I think the list is great...but just IMO it might be the most effective if formatted in a "Top 20" list or something similar. Technically every fish should be a "Think Twice Fish."
JMHO