I won't be doing any classic Who here because I've only seen a handful of episodes. I'm on the Third Doctor and I've only seen what's available on Netflix. This will be the cast that have appeared since 2005.
1. Ninth Doctor: Natalia Tena ('Doctor')
I've only seen Natalia Tena in a few things (About a Boy, Harry Potter, and Game of Thrones), but I think she could pull off the Ninth Doctor. He's quirky, but I always felt he was a bit more intense than Ten and Eleven. I get the vibe that she could pull off that playful yet fierce personality.
2. Rose Tyler: Aaron Taylor-Johnson ('Rhys Tyler'. Even though there's a character by the same name in Torchwood.)
This may not be the best pick, but this was really hard. Rose is a lot of fun, strong, smart, but kind of naive and Johnson could probably pull that off. He looks young enough (when he's clean shaven) to pull off the naiveté thing and Kick Ass proved he can layer it up.
3. Captain Jack Harkness: I just can't...
I kept putting different women next to him, but I just can't do it. John Barrowman is a very unique actor and he's just so perfect for this role. I can't imagine anyone, male or female, as Captain Jack.
4. Tenth Doctor: Amy Acker ('Doctor')
I thought this one was going to be crazy difficult, but once I remembered Amy Acker, there was no contest. Her skills embody the Tenth Doctor and she does everything perfectly. Plus, she's adorable. Not as adorable as David Tennant in my opinion (come on, it's me we're talking about here), but look at how cute she is!
5. Martha Jones: Chiwetel Ejiofor ('Marcus Jones')
Martha Jones. The doctor turned soldier. The only thing I don't love about her is how in love she is with the Doctor and how much she pines over him. In this wacky gender swapped version, Chiwetel Ejiofor doesn't fall in love with Amy Acker. And yes, it is a coincidence that these two have both worked for Joss Whedon. You'll probably see more. Anyway, Ejiofor has been great in everything I've seen him hin and I feel like I don't see him enough. He'd be a fun companion. Even though I don't know how to pronounce his name.
6. Donna Noble: Simon Pegg ('Dennis Noble' cause it sounds better than 'Dexter Noble'.)
Donna is for sure my favorite companion. Well... she's at least tied with Amy/Rory. But she's tied with them by a lot. If that makes sense. Basically, I love her. One of the main reasons I love her is because I love Catherine Tate. I also love Simon Pegg, which is one reason why this works. They're both fantastically funny (their style is very different, but I love them both), they're both ginger, and can't you see Simon Pegg being super good on-screen friends with Amy Acker? They probably know each other already. I'm thinking of a very specific picture with him and several other actors I love at Joss Whedon's house. Chances are they've crossed paths. Then Amy would tell Joss to put Simon in all his movies and I would be that group's cooky non-entertainment industry friend until they get me a job as a movie researcher (it's totally a real thing and I've decided it's another dream job) and my life would be complete.
7. The Master: Emma Caulfield ('Master')
I really like John Simm as The Master. Just the right mixture of crazy and scary, and I've seen Emma Caulfield work that same magic. Plus, hey! More Whedonverse. Although I'm starting to get concerned about how many actors here are American...
8. Eleventh Doctor: Felicia Day ('Doctor')
Come on, you knew I was going to use her eventually and I'll probably use her a lot more. Even this is hard to picture because even the way Matt Smith moves is nutty, but if anyone could pull it off, it would be Felicia Day. Man, I want to be friends with her...
9. Amy Pond: Alan Tudyk ('Ftizwilliam Pond' because I'm tired of coming up with names)
I have roughly the same reaction when I see these two. It has to do with smiling and fangirling. Seriously, if I was gay, I'd totally have a thing for skinny red headed ladies cause I kind of have a thing for skinny red headed ladies now. If either of my skinny red headed friends are reading this, know that I don't have a crush on you and I wish you well with your respective husbands.
I just like this switch up. Amy has a sultry appeal with a hint of nerd and Alan Tudyk embodies that. Although he'd probably play the role with more nerd and I'd be absolutely okay with that. Also, he wouldn't be 21 when he runs off with the Doctor.
10: Rory Williams: Kelly Macdonald ('Rory' cause it's a girl name too)
For some reason I'm getting really excited about Kelly Macdonald and Alan Tudyk being an on-screen couple. I don't see her nearly as often as I should. She could totally pull off the awkward, flannel-wearing season 5 Rory and the sexy, hipster season 7 Rory (Keep in mind I don't find hipsters sexy. Rory happens to be a hipster later on in the show and I happen to find him sexy as well). Am I the only one who finds that transformation a bit odd, by the way?
11. River Song: Lee Pace ('River Song' cause otherwise Melody Pond wouldn't make sense. Although Melody is definitely not a girl name... and Melody translated into Gaelic is Fonn and Fonn Pond is lame. As is Alaw Pond [Welsh for Melody]. Steven Moffat is obviously much better at playing on words than I am).
Another actor I just want to see more of. I figured he wasn't going to be in the first Hobbit movie and then during the preface I yelled, "THRANDUIL! THRANDUIL! THRANDUIL'S RIDING A FREAKING DEER!" Not out loud, of course, but I probably fist pumped at least. But this should give you an idea of how much I love Lee Pace. Cause I love him a lot. He and Bryan Fuller make for television beauty (go watch Wonderfalls and Pushing Daisies right now if you haven't) and I'd really like to see Lee Pace in a role like this. Less like the Pie Maker and more like... well, River.
That post took me a lot longer than it should have. With the exception of not being able to come up with anyone for Jack Harkness, I feel good about my decisions.