This week, I told you about Liz Dolan, once Nike’s global marketing boss, joining Oprah Winfrey to be CMO of her new venture, the OWN cable network. And yesterday, my colleague Jessica Shambora wrote about Ellen Kullman, No. 15 on the Fortune Most Powerful Women list, stepping into the CEO job at DuPont.

Meanwhile, Meg Whitman, No. 1 on our MPWomen list when she was CEO of eBay , popped back on the scene with a new career plan: She’s going to run for governor of California. It’s not official yet, but Whitman signalled her intentions by quitting her three public-company boards – eBay, Procter & Gamble and DreamWorks Animation. We’ve been saying for months here on Postcards that the boss who built eBay has her eye on Arnold’s job. Schwarzenegger, that is. His two terms will be up in 2010, and term limits preclude his running again.

Another Silicon Valley leader (and MPWomen list alum) may be landing a new CEO job: Carol Bartz, as the Wall Street Journal reports, is a contender to be Yahoo’s next CEO. Bartz is smart and tough, with loads of experience, having built Autodesk during 14 years at the helm. With $2.2 billion in sales last year, Autodesk is one-third Yahoo’s size, but Bartz has big-company perspective since she sits on the Cisco and Intel boards.

I’ve gotten to know Bartz a bit through Fortune‘s Most Powerful Women Summits, and I’ve even ridden backroads buses with her at other Fortune confabs, from Aspen to India. You always know where you stand with Carol. She’s as candid as they come. If the Yahoo board picks Bartz or another outsider – which is likely to happen next week, I hear – will Yahoo President Sue Decker opt to stay or go? Decker, who is No. 39 on Fortune‘s 2008 MPWomen list, has wanted the top job and been a serious candidate.

Here in New York City, meantime, there’s lots of shakin’ inside Merrill Lynch, now part of Bank of America . Greg Fleming,  John Thain’s No. 2 at Merrill, announced that he’s leaving to become a senior research scholar at Yale Law School. I don’t know Fleming, who is just 45, but I’ve met him, and I’ve long expected him to have a bigger banking gig someday. Fleming’s exit follows brokerage boss Bob McCann’s, announced earlier this week. General counsel Rosemary Berkery is out as well; she’s never made our MPWomen list but we considered her every year. Clearly, BofA chief Ken Lewis is putting his stamp on Merrill – quickly!

One more major move to note, this one up in soggy Seattle. Gerri Elliott, head of the worldwide public sector at Microsoft , is leaving to spend time with her family. Seriously spend time with her family (this isn’t one of those charade firings). I hear from folks at Microsoft that her departure is a big loss. Joining Microsoft from IBM, where she spent 22 years, Elliott went on to build the public sector business – selling software to government, education and non-privatized health-care customers – from $4.7 billion in revenues in 2004 to $8 billion today.

She told me in an email this week: “This was a super-tough decision for me as I had the best job on the planet. But I am really needed at home. Our youngest, Jessica is a junior in HS and wonderful, and I really wanted and needed some time with her before she goes off to college. We blinked and our son was off!”

She went on: “This isn’t retirement retirement. What is the right word to use when you know you’re taking a break to be with family for a bit before you find that next great gig you know you have to do? Whatever it is, that’s what I’m doing. Immediate goal is to get on several boards where I know I can add value.”

Don’t you think we’ll see more shifts like this – powerful people asking, “Is my job worth my stress – and what else should I be doing with my life?”

On that note, have a nice weekend. Relax!