Tech companies are rethinking their identities. IBM may buy Sun Microsystems. Cisco is moving into the server market, and also mightily into the consumer space. The latest move by Cisco CEO John Chambers–whose family reportedly owns eight Flip cameras–is a buyout of Pure Digital Technologies, which sells those ultra-simple videocameras. (I love mine.)

Powerful people are busy rethinking their identities too. My  last two stories in Fortune are about ex-CEOs reinventing themselves. One is on the new cover story: Former eBay CEO Meg Whitman is putting her all–including $50 million in personal funds, she ventures to guess–into the race to be California’s next governor. (The Golden State, the sickest state in the nation by many measures, needs reinvention too.)

Before Whitman, I profiled former Viacom CEO Tom Freston, whom we call “The Most Wanted Man on the Planet.” We’re being a little facetious, but since Freston got ousted by the media giant’s octogenarian chairman, Sumner Redstone, in 2006, he’s been in high demand and having the time of his life. Freston is helping Oprah Winfrey start her new cable network, OWN. The first lady of TV is busy recreating herself too.

Bad times are good times to redefine yourself. I recently had dinner with Jim Donald, the former CEO of Starbuck , who got fired by chairman Howard Schultz early last year. Schultz retook the reins as CEO and is struggling. (Who would want his job?!) Donald is enjoying his unemployed life. He’s on the speaking circuit, teaching a class at the University of Washington, serving on boards, and is being wooed by Bill Ackman, the activist hedge fund investor, to help him fight for seats on the Target board. (That’s a messy matter that Donald might best avoid–my opinion, for what it’s worth.) Meanwhile, Donald has gotten in serious physical shape. He recently won his age group, 50-54, in the Northwest Indoor Rowing Championship. Fame is fleeting, though. The ex-CEO of Starbucks just turned 55.

Others too are deciding to hang it up at that age. Two weeks ago, on the day after she turned 55, Procter & Gamble president Susan Arnold quit her job. She essentially took herself out of the running to succeed CEO A.G. Lafley (Bob McDonald has long had the edge). Judging from the chat I had with Arnold on that day P&G announced her move, I think she’ll be out of the corporate game for a while. The boss who was No. 7 on Fortune‘s 2008 Most Powerful Women list wants to regroup. (See “Why P&G’s president quit.”)

Reinvention is clearly the trend. Last weekend in Arizona, when I was mini-vacationing to escape the New York stress, my hiking guide was a former lawyer who quit the rat race to lead mountain treks. This guy said he’s never been happier than he is now. Two nights ago at a Most Powerful Women dinner, I heard about one lawyer who just became an acupuncurist and another who turned herself into an entrepreneur. She’s selling her inventions on HSN.

This weekend, think about your life. Don’t leave what you love. But figure out who you are and what you really want to do. There’s less shame than ever in losing your job–in failing. Life is a trampoline. Use it to rebound. – Pattie Sellers