Now, before you tell me I'm crazy, I'm going to put out a good argument as to why he should, and then why he probably won't. Plus, a few of my fellow Screen Rant writers chime in on why I may be wrong in an Oscar nod for RDJ.
First things first, as to why RDJ deserves to be nominated: Hollywood, and pretty much everyone else, loves a comeback kid. And RDJ is the king of making a major comeback. His acting career is nothing short of amazing, and he is one of the most versatile actors of his generation.
But he also had a troubled life, flirting with drugs and alcohol. However, Downey Jr. is a new man, and he's been ready for his comeback for a couple of years now. The first step was landing a major role in Shane Black's amazing Kiss Kiss Bang Bang. Though the movie didn't do great at the box office, it cemented his (and co-star Val Kilmer's) reputation as someone of whom we should take notice.
The second reason why RDJ deserves to be nominated is his starring role in Iron Man. That big breakthrough came in 2006 when, after working as hard as he could, RDJ landed the role of Tony Stark/Iron Man in the movie that would redefine his career.
But instead of giving a run-of-the-mill performance, he brought humanity and realism to the role of a vain, brilliant, and wealthy businessman who finds redemption in a cave in Afghanistan. The humor, joy, pain, sorrow - all of it - with help from the excellent direction by Jon Favreau, Robert Downey Jr. gives us a believable yet flawed character who truly grows by the end of the movie.
Third: RDJ, and Iron Man--a mega box office and critical success. Entertainment Weekly recently named him the entertainer of the year, thanks to Iron Man and Tropic Thunder, while Wizard Magazine (which primarily covers comic books) said that Iron Man wasn't just the best film of the year, but the best comic book film of all time! I honestly thought The Dark Knight would achieve that coveted spot.
Lastly, Iron Man scored major critical kudos, sitting at an extremely comfy 93% rating at Rotten Tomatoes. The film made more money than the fourth Indy film, and was number two in the North American box office at $318 million +, much more than anyone predicted it could, including yours truly. It sits at over $580 million worldwide. Clearly, fans loved the film, the people behind it, and of course, RDJ's performance.
Oh, and one of the most important critics, Roger Ebert (I'm a big fan, going back 18+ years), listed Iron Man as one of the top 20 best films of 2008, and hailed RDJ's performance. (He also praised The Dark Knight, which I agree is the other great film of 2008.)
Bruce Simmons, one of my fellow writers here at Screen Rant, had this to say:
"'Iron Man' is more of an emotional culmination to screen of many many comic book fans, like myself or Vic Holtreman and the rest of the fandom that spit-drooled all over themselves when they saw this culmination of fantasy being given a life on the screen. Top notch fulfillment as far as I'm concerned."
"Unlike something like Batman, where it's a man in a costume, the effects that went into bringing the armor alive in 'Iron Man' really did it for me. It wasn't exactly as I imagined it, but it was perfect for what it was."
Also, RDJ has flirted with Oscar before, receiving a nomination for his role in Sir Richard Attenborough's Chaplin film in 1992. Though he didn't win, the nomination proved he has acting chops. A great run on Ally McBeal earned him an Emmy nod and a Golden Globe win.
Even if RDj is nominated, the chances of his winning are, honestly, not so good. He's a dark horse just to be nominated. Heck, many think RDJ should be nominated for his supporting role in Tropic Thunder, which I have to admit, I really need to see. (Yeah, I stink for not seeing it! I don't watch a lot of movies lately, due to a very busy schedule.)
Now if RDJ isn't nominated for Iron Man, I'm guessing the visual effects and sound will be nominated and may even win, though some felt the FX weren't all that great. I disagree--the visual effects were some of the best I've seen in years! Will the film win, or will it be an upset, like when Transformers lost to The Golden Compass? I hope not!
So why wouldn't RDJ get nominated for Iron Man? Well, probably the easiest answer is a simple one: It's a comic book movie, and we all know those don't fly so well in the Oscar categories, other than tech awards. Plus, a certain Bat may walk home with some noms and awards.
And The Dark Knight, by Christopher Nolan, deserves as many Oscar noms as possible, and if nothing else, Heath Ledger should win as one of the greatest villains in film history. Yes, I'm on that bandwagon, and yeah, I think he was absolutely wonderful. Aside from everything else, Heath's eyes kept shifting and blinking, belying the insanity underneath the Joker's green hair and white make-up.
Robert Keyes, another one of my fellow Screen Rant writers, echos what many feel about RDJ not getting nominated:
"I can't see 'Iron Man' getting any Oscar Nods - It would be like the 'X-Men' films getting one. Not even the special effects were on par with other flicks. As for Downey himself, in my opinion, he certainly does not deserve even a nomination and in my mind doesn't even come close to leading male roles in any other film this year. I love the guy, loved the movie, love Marvel, but that role isn't even in my  top 20 for acting performances or challenge."
Nicely put, but I'm kind of sick of the dry, sometimes depressing art house movies and their performances. Indie films aren't what they used to be, and neither are art films, in my opinion. I'll have to explain that further in another article, but I feel the great indie directors of the 1990s and earl 2000s are making the best movies, comic book or otherwise, like Favreau and Nolan.
And if nothing else, these creators are helping to put legitimacy into the big blockbusters and comic book films, something I don't think we've seen in years. I think the 1990s killed good blockbuster films, while giving us great indie films.
Finally, Screen Rant grand poobah Vic Holtreman had this to say about the idea:
"Well he certainly shouldn't get an Oscar for 'Iron Man.' I could see some sort of nod for Tropic Thunder, but there's no way he'll win an actor Oscar for a role in a comedy film. In Iron Man he was fine, but certainly nowhere NEAR Oscar worthy IMHO."
Anyway, I really hope Robert Downey Jr. is recognized for his performance in Iron Man by the Academy Award voters, even if it's a nomination.