Fan-casting Ant-man

Rumors abound for Ant-man casting, specifically Joseph Gordon-Levitt and Paul Rudd. While I believe JGL could act the role of Pym, I don't see him fitting physically. I also envision someone a little older (though, who knows what Marvel's plans are). Rudd might be able to pull it off too, but I don't know if I could take him seriously as Pym.

So, who do I think should address the Pym particles and don the cybernetic, ant-communicating helmet?

Nathan Fillion

For those that remember Joss Whedon's short-lived TV series "Firefly," Captain Malcolm Reynolds (played by Fillion) is essentially Henry "Hank" Pym. Fillion nails the attitude while at the same time showing the heart of this seemingly cold character. It wouldn't be a stretch to see him as the brilliant, yet brash Pym.

Moving on, we can't have Pym without Janet Van Dyne a.k.a. The Wasp, and since we're on a "Firefly" kick...

Morena Baccarin

Fillion and Baccarin have the chemistry AND tension that would come with these characters. For the love of Whedon, go back and watch "Firefly" to see for yourself. Baccarin has the pep to take The Wasp in a very nice direction. And with the lack of female silver screen supers, Baccarin being a wonderful ensemble actress (not to mention a kick-ass solo one), she would add some great acting chops to the female Avengers cast.

UPDATE: The MCU is going in a different direction then I originally thought, with Michael Douglas cast as Hank Pym and Paul Rudd as Scott Lang. No news on The Wasp, but it's rumored that they are considering Pym's daughter in the role.

Fan casting the protagonists for this film may be in vain at this point, if rumors are to be trusted; however, what about the antagonists? I've heard a lot of dream castings for the two above, but let's talk villains for a moment. Ultron is the quintessential Pym villain, but that is clearly changing in the MCU (for better or worse). We may not have an idea of what Edgar Wright's planning at this point (correct me if I'm wrong), but let's take a look at some of Ant-man's recurring enemies:

Egghead/Tom Hanks

While he continues to whine about not being asked by Marvel to join the ranks of the Avengers, I could see Tom Hanks destroying as a villain. Egghead seems to be one of the most realistic of Pym's adversaries (albeit, goofy and not very intimidating) and Hanks could stand in a long line of great acting MCU villains (Hugo Weaving, Jeff Bridges, etc.). Shave that head of yours, Tommy. I have a feeling it's a little egg-shaped anyhow.

Or are you more interested in a villainous ...

Simon Pegg

Quite the possibilities.

The Porcupine/Robin Williams

You may be cringing just thinking about this, but I think Robin Williams would be a fantastic villain and The Porcupine could be just the role for his talents. With connections to Justin Hammer and The Zodiac (have you seen the Agent Carter short yet?), this could be a MCU connecting opponent, as he's fought the likes of Cap and Shellhead in the comics, though I'm not sure what he would add to Phase 3. I also could picture Burt Reynolds in this role.

The Living Eraser/Terry O'Quinn

While it seems doubtful that Wright would go in this direction, to me it makes the most sense with Phase 2 leaning more towards space and 3 towards magic (Ant-man will show up in Phase 3). Terry O'Quinn could be an awesome alien, sending people into Dimension Z. If this antagonist is placed in the mix, O'Quinn could truly bring this character to life well.