Observers have spent the last year wondering if anyone could fill the shoes of Oprah Winfrey, but lately, a new obsession has taken root: Who might replace Regis Philbin as the co-host of Live?

There are a couple of variables to consider here. One, due to the increasing amount of time Regis has missed in recent years, for health reasons among others, a lot of potential contenders have already had experience sitting in for him, and testing their chemistry with the bubbly Kelly Ripa. And second, anyone who comes on board Live will likely be expected to fill a slightly different role than Philbin has had. As Ripa has become more confident on the job and as Regis has spent more time away, he’s gradually deferred to her more and more. The newcomer will have to play well with Kelly, who is probably going to remain the key member of the new pairing even if her name comes last in the title.

On to examining some of the contenders whose names have popped up here and there:

Jeff Probst: What’s not to like? He’s a big name, a proven interviewer, and someone without a long-term contractual commitment to worry about. And let’s face it, you can’t do Survivor forever. At 48, he’s slightly older than Ripa, which is the setup we’re familiar with from male-female local news teams. My guess is that if he wants the job, he can have it, unless some truly huge name like Matt Lauer came on the market.

Ryan Seacrest: The Live producers would be crazy not to look into the possibility of getting him, but at first glance, it seems like he would be too boyish to team with Ripa. The bigger issues with Seacrest are how much he has going on in his life already, and the amount of money he makes from American Idol. Would he want to take less loot to do more work? Unlikely.

Anderson Cooper: Given his frequent co-hosting appearances, his rapport with Ripa, his skill at interviewing, and the fact that he’s a New Yorker through and through, he’d be the overwhelming choice to replace Regis – if he wasn’t already slated to host his own daytime show beginning this fall. But if the new show doesn’t work out – and the failure rate for daytime newbies is scary – then Cooper might get another shot someday.

Neil Patrick Harris: He’d be the ideal get. Harris is quick-witted and has a wide-ranging love for all forms of pop culture, from the trashiest to the most serious. The biggest problem with Harris applies to several others on this list too: He just has too much else going on right now that would conflict with a fulltime job in New York City. It’s one thing to host an awards show every so often, another to make schmoozing celebs your entire life.

Mario Lopez: While he’s still sort of an actor, based on the last several years it appears that his future lies in hosting. He acquitted himself fairly well on the mostly forgotten “male version of The View” called The Other Half, and would probably be a decent pick, if not a game-changer. But it’s questionable if native Californian Lopez would want a fulltime job in New York.

Howie Mandel: At one time, this would have seemed like a positively insane idea, but that was before Mandel proved himself to Real America hosting the ultra-middlebrow Deal Or No Deal and arguably improved America’s Got Talent. Playing off another host might be a problem for the occasionally manic Howie, but he’d be worth strong consideration if he wants the job.

Billy Bush: It’s hard to know if he has the chops for a show like Live, given that his radio show and his duties on Access Hollywood aren’t exactly an intellectual stretch. He’d be a safe choice, but whether he’d want to give up his current jobs or Los Angeles is questionable.

Chris Harrison: We like to make fun of his not-quite-taxing duties with The Bachelor franchise, but his 60 seconds of airtime every week has put him on many a post-Regis list. I’m not sure he could get used to the increased workload, and his biggest interview ever, the totally biased trainwreck that was Jake vs. Vienna, doesn’t inspire much confidence he could handle even celebrity fluff.

Mark Consuelos: He’s mostly known as Kelly’s husband, but what you probably don’t know about Consuelos is that he’s also … well, OK. He’s really just Kelly’s husband. And that’s the problem. Unbeatable chemistry with the existing host is all well and good, but how would they keep the show from becoming too insular? Would he really want a job that would just exacerbate his “Mr. Ripa” problem? And if things didn’t work out, how do you fire the new guy without also losing Kelly?

Daniel Tosh: The Tosh.0 host has gathered a surprising amount of support, given his low profile with the sort of audience that tunes into daytime TV. But given Tosh’s lack of a background conducting interviews, and the controversial nature of his comedy, it’s hard to see how this would work.

Tom Bergeron: As Dancing With the Stars doesn’t look like it’s going away anytime soon, coaxing Bergeron to New York is probably impossible. But it might be smart to look into it: He’s a proven success at live TV, is a great ad-libber, and after trying to carry the likes of Samantha Harris and Brooke Burke for the last several years, he’d no doubt appreciate being able to play off someone equally witty.

Lisa Rinna: This name has gotten a little play lately, but aside from the obvious questions – is anyone really interested what Lisa Rinna has to say about anything, and would anyone really want to look at that face five hours a week? – a two-woman team seems like such a huge change from the norm that I can’t see it being considered. (The same goes for the other woman who has popped up on a few “maybe” lists, Kathy Griffin.)

Bryant Gumbel: He’s been relatively underemployed since leaving the CBS Early Show, but he’s co-hosted before and seems to get along well with Ripa – surprising considering he often gave off a vibe of not being able to stand Katie Couric on Today, and who is more like Katie than Kelly? Few are better at this type of format, but Gumbel probably has too many controversies in his past to be viable for a role like this, assuming he even still wanted the workload.

Nick Jonas: He’s been mentioned because he’s co-hosted the show in Regis’s absence before, but can we get serious for a second? I can see why Nick might want to explore new career options, since Bieber Fever seems to have made the Jonas Brothers one of its casualties, but there’s no way they’re going to pair Ripa with someone young enough to be her son.

No one: Remember how Ripa got the job to begin with: She had her first chance to co-host Live near the tail end of a long period where the producers were testing who had the magic chemistry with Regis, following the departure of Kathie Lee Gifford. Though Ripa was a fairly obscure soap actress at the time, viewer response quickly made it clear she was the one. So why rush into naming a permanent replacement? Give several their chance a week at a time, and see what happens. The need for a long audition process might not be as drastic this time because so many of the candidates have already filled in for Regis on occasion, but now everyone would know the stakes.