This is one of the very few times I disagree with you SkiFletch, as well as Chac and everyone else, but here goes...
Considering that Clownfish actually are classified as Pomacentrids (Damselfishes) I'd imaginge it woudn't be a big deal to have the Damsel in with the Clown. I have seen many people, including myself, keep Damselfish with Clownfish, Gobies, Blennies, Dwarf Angels, ect, and even Dragonets with little or no incident. I think that the aggression in Damselfishes is very exaggerated, and considering that many people are so afraid of Damselfishes that they would never risk keeping them, that actual experience is very limited and people just end up believing what other users tell them.
I personally think it is a very sad thing that people hate Damselfishes so much. They are amoung the most common marine fishes in the world, and adding to that is the fact that they are amoung the easiest of all marine fish to breed, their is relatively very little risk of them becoming endangered in wild when compared to many other more desirable species. The populations of wild Tangs, Angels, ect. are continuously on the decline due to them having to be collected from the wild because they are impossibly difficult to breed in the aquarium. Damselfishes are also very intelligent, very colourful, and very personable. An interesting fish as a whole, very much like a kind of colour-charged, fast, and cute Cichlid. I personally love both Cichlids and Damselfishes, however, both of them do need their own variety of care.
I think that the real problem with Damselfishes losing their desirablity is not their aggression, but the fact that they are losing their novelty.
We can put aside tanks for Mbuna and other Cichlids; why can't we do the same for their salty cousins? (who I believe have the advantage, because they
can be easily accomodated with other aggressive fishes)
-Lynden