Probably the best list I've seen.

http://www.talkorigins.org/faqs/faq-transitional.html

A living transitional fossil...

I'd just LOVE for any evolution skeptic to explain the data presented in this image...

I think it's some sort of primate fetus/infant (which, dictionary defintion-wise, doesn't really rule us out)

So yeah, it is a human fetus

Wikipedia is fascinating.  Before I know it I'm reading a science journal about inducing tooth growth in chickens by reactivating dormant genes.

 Anyone who asks for a transitional fossil is proving that they have no idea how evolution works.  Every living thing on planet earth is a transitional organism, so EVERY fossil is a transitional fossil.

A great book that's easy to read, and makes a wonderful Easter gift for any YEC friends is "Your Inner Fish" by Neil Shubin.  It explains (and has pictures of) several of the most important transitions in our evolutionary past, including the move from fin to arm.  It ought to be required reading for every high school freshman biology class.

Canis and ursidae: http://www.fossil-treasures-of-florida.com/bear-dog.html

Looks like an awesome pet.

edit: Since creationists use dogs and cats so much in their anti evolution rants.

Yay!  For my tattoo!!!!

Small nit-pick - not all forms would be transitional. 

We should exclude those suspected to be on the very verge of extinction.

But that would be a very small fraction, and rather hard to identify with confidence as the last of their line.

http://www.ted.com/talks/lang/eng/douglas_adams_parrots_the_universe_and_everything.html

Here is a link to a speak by Douglas Adams where he speaks about several species adaptations including the Dodo. Good stuff.

Well, I guess if we're being nitpicky, we can say that only individual organisms which reproduce are transitional, which would actually make a significantly higher number of them non-transitional.  But that's only if we think of "transitional" and "organism" as separate words.  We could think of "transitional organism" as a term which applies to any organism whose DNA is modified from its parents and whose offspring, whether actual or potential, would also be subject to modification.

We'd still have some issue with asexual clones and a few other nit-picky quirks of nature, but that would avoid the problem of having to guess whether this fossilized crocoduck actually had offspring or not.  

 Well, I think we're just quibbling semantics.  The point of saying "every organism is transitional" is to say that every organism is part of the evolutionary system, which is descent with modification.  My parents are a "transition" between my grandparents and me.  Yes, we're the same species, but I am a continuation of the process of generational modification of a line of DNA.  

With the weird caveat that we haven't completely disproved the remote possibility of successful macro-mutations between one species and another in one generation, it's safe to say that no fossil marks an "absolute transition" between species.  Everything we call a transitional fossil is a plant or animal whose features illustrate part of the evolution of new adaptations, such as fins becoming limbs.  But when we look at Tiktaalik, for instance, we're not seeing an isolated individual that was the sole link between forms.  There were certainly thousands, hundreds of thousands, or perhaps even millions of individuals, any one of which looked essentially like its parents.  

Speciation can only be identified in retrospect.  Who knows which individual [iTiktaalik[/i] was the one whose genome contained the "spore" for whatever species followed it on the evolutionary tree?  In the same respect, who knows if I have a mutation which would lead -- in a hundred thousand years -- to a totally new species?  We just can't know until it happens, since virtually every organism has mutations/reorganizations which could, in theory, lead to new species.  So I think it's perfectly proper to speak of every organism as transitional, so long as we understand that every individual is not going to propagate a new species, but in theory, each individual could.

The Creationists still seem to be asking us to show a 'transitional' form between completely different species/lineages - many of them actually take the infamous 'crocoduck' as serious example of what they expect us to show if evolution were 'true'.

So they just don't get the idea that evolution is a step-by-step process.

Our argument that if you could see representatives of every generation along the entire lineage of any 'species' we know of today, nowhere would you see any difference from one generation to the next greater than you would expect to see between a parent and its offspring, just doesn't get through to them.

Well, to concede that would to admit their argument against evolution had holes in it, and since they know evolution is not true, there cannot be any 'transitional' forms, so that's all there is to it, you dumb atheist.

But even back before Darwin, people had classified animals into plausible family trees showing how you could go from one species to another similar one in a consistent direction, so the evidence for the relatedness of so many species has been around all this time. Its like the 'God-of-the-Gaps' argument, they will ignore all the evidence that fits, and seize on the gaps where intermediate forms just did not split off into separate species or just died out.

Its funny, they will use the absence of surviving intermediate forms as evidence against evolution, and then ask, 'if we evolved from apes, why are their still apes?' So whether there are intermediate species or not, its still evidence against evolution...

 Yeah.  Monotremes are transitional forms that just happen to be lucky enough to still live.  I think this highlights another misconception many Creationists have of evolution.  They seem to think that evolution is somehow "done."  But there's nothing in evolutionary theory to suggest that there wouldn't always be transitional forms.  We'd be kind of shocked to see a world where there weren't any, in fact.  

Another really good example of transitional forms is any one of several existing ring species.  Of course, Creationists will poo-poo ring species because "they're just variants of the same species," but this highlights their misunderstanding of the concept of species, which has actually been rendered sort of quaint and outdated by modern evolutionary theory.  In the classic example of the heron gull and black backed heron, the two species do not interbreed, but there's still a complete, unbroken chain of populations, each of which interbreeds with the surrounding populations.  In other words, if we imagine bending a 1 foot wire into a circle, neither end would be joined to the other, but as we move around the circle in either direction, everything is joined.  That's how a ring species works.

Well, I don't think that monotremes are really a good example of a transitional form. Yes, everything is transitional as noted above and I have already mentioned that I have reservations on the matter.

That being said, monotremes lay eggs and other mammals do not. Since nothing lays half an egg, I don't really want to get into this with the YEC crowd. It is just not a great position to take.

Basically, we all know what is what. However, adding to that, everything that now exists can rather easily be seen as a terminal to evolution. This does not deny everything that happened up to the current moment, nor does it say anything about what will happen in the future.

Sticking to transitional fossils though, I fail to see how not having one would even be a valid point. OK, we do not have everything. SFW. Here I am reminded of the 19^th century concept of the “missing link”. Of course in the modern world, we have plenty of transitional forms between the rodent like creatures that went into the trees many millions of years ago and what eventually came out.

However, the fact that we simply do not have every intermediate form does not show anything at all. Sure, the link may well be missing (in whatever sense that makes). That does not mean that it never existed.