My definition of "Doctor's companion" may be looser than some's. I've expanded it to one who travels on the Tardis through time and/or space and either chooses to travel or embraces the journey. This latter qualification is the difference between Rose's mother making the list or not. I've decided not. Jackie Tyler never really embraces the journey. She boards the Tardis mainly for the purpose or getting her daughter back or getting the hell back home. While some of the list below are Tardis-kidnapped like Jackie occasionally was, they eventually got into the spirit of the thing, accepting, learning, and growing from the experience. Or they just wantonly hitched a ride with an alien. Either way, here are my top ten companions from Doctors 8-11 in descending order.
[contains spoilers through season six, and mild season sever spoilers -- I've stayed away from the biggies]
10. Dr. Grace Holloway. Welcome to 1999 via 1996. The smart, moral, cultured, disciplined, career driven woman who has a gorgeous if foppish boyfriend who can't come to terms with her demanding career cutting into their relationship. It's a very early-to-mid-1990s relationship crisis. Not to mention the whole thing feels like a giant tipping of the hat to the first two films in the Terminator franchise. But Dr. Holloway is great from a feminist point of view: she's not only smart and powerful, when the hospital head honcho says go against your integrity and cover this up she tells him stick it up your ass, and quits. Which is nice plot-wise because it frees her up for an adventure with a rather uninteresting Doctor. But Dr. Grace first falls for the Doctor against what would seem to be her better judgment only to have rationality rear its head and by the time she believes again she's become a bit of a worry wort. Terribly hard to like. Sorry Dr. Grace Holloway, you're the bottom of my list.
9. River Song. I could not get into the River Song story line. In the library episodes when she first appears, River Song presented a fascinating conundrum -- intersecting timelines that never meet in order. Wait, isn't that the plot of The Time Traveler's Wife? In this case, The Time Traveler's Time Traveling Wife? Theoretically I love the concept of two people falling in love with each other because when they met the other, the other was already in love with them. And I think if we'd seen the chronology from River's point of view, I would have enjoyed it the way I did Daughter of the Blood from Anne Bishop's The Black Jewels trilogy. But I never found a way to enter into this story line and let it sweep me away. River and the Doctor bickering like a married couple was charming, but the apparent age gap between the actors threw me -- what can I say, Time Lords screw with my perception of who is an appropriate couple.
8. Sarah Jane Smith. I don't dislike Sarah Jane, she's just not up to snuff with my third wave feminist notions. Oh yes, she's the intrepid explorer who doesn't want to stay safe or stay home -- Well done, Sarah Jane. Well done. -- but when she runs smack dab into daleks, she's a bit too quick to throw her arms over her eyes and scream like a damsel in distress. When Sarah Jane talks to Rose in season two, we get the impression that the Doctor leaving Sarah Jane ruined her life; she couldn't ever get back to "normal," because she didn't want to and she didn't know how. While it appears that The Sarah Jane Adventures portray a further tale where she reclaims much of what she "lost," I still dislike the feeling I get that the character thinks it's been "taken away from her," and frankly, I don't do victims.
7. Amy and Rory Pond. The Ponds, as we come to think of them over season six, are the ones who waited. Two of Amy's voyages are among my all time Doctor Who favorites because they feel like Classic-Who to me: "The Beast Below" and "Vincent and the Doctor." But I could forget all of season six without regret. From a plot or gender-theory point of view, the Doctor traveling with a married couple is a fun new take. Doctor-as-third-wheel is an interesting bit although the uber-nerdy Matt Smith portrayal may take this overboard. Their attempts to reconcile youthful travels-with-the-Doctor with the "average" life of the settled 21st century earthling is endearing, and very much a contemporary struggle of interest. Although personally speaking, there are other struggles I find more emotionally intriguing (and emotionally intriguing trumps intellectually intriguing any day) such as Rory, initially a pushover, managing to find his own ground to stand on, and both Rory and Amy coming to recognize the other as strong and just as much in love as the other. Amy-the-little-girl and the Doctor is a heart-wrenching tale, one that is seemingly an absent-father tale where the father figure spends the rest of her life trying to make it up to her. In the end, he can't save Amy-the-woman, but at least he has another chance to save Amy-the-little-girl. Someone very old and very kind, the last of his species, who can't stand to see children cry. I respect the Ponds, but I never came to love them as more than a lens through which to view the Doctor.
6. Wilfred Mott. Donna Noble's grandfather just about breaks my heart (in a good way) every time he appears on screen. From the first time we meet him, conversing with Donna around the telescope he has pointed to the sky, to the moment Donna does her blue-box-flyover, to Wilfred's discussion with the Doctor on what it is to be an old man, to the moment the Doctor leaves Donna and Wilfred tells the Doctor that no matter what, he'll wave up at the sky every night, for him and for Donna, so that the Doctor doesn't have to be alone. Wilfred is a fabulous foil to the Doctor; we often forget that the Doctor is an old man due to his youthful face, but next to Wilfred, we realize how similar the two are. They're seen a great deal of the world and feel it keenly, although Wilfred, unlike the Doctor, is actually able to express those feelings.
5. Captain Jack Harkness. You're never sure whether to love Jack or be suspicious of him. The Doctor is suspicious, and with good reason -- Jack's pulling a con when we first meet him. But Jack is rather lovable. An incorrigible flirt ("Jack stop flirting." / "I was just saying hello." / "For you that's flirting.") and he's just as quick with the witty line as the Doctor, he's great fun to be around, and not at all hard on the eyes. We get to see more of his backstory in Torchwood but like some other characters, we get to see his eventual death before we ever see his beginning. Crossed timelines and all that. It's also easy to love Jack because, like Martha, Jack loves the brokenhearted Doctor. Some of my favorite moments are when Jack and Martha are commiserating about men who don't even think to look at them because they're still in love with some blonde.
I'm neck deep in my Doctor Who indoctrination period, so please pardon my rabid descent into unbridled fandom. I started with the Ninth Doctor and have not yet caught up to the newest Doctor. Yet I'm both regressing and progressing in terms of timeline ... which, coincidentally, feels very situation appropriate. Like Tardis via DVDs.