Steve Ballmer
"He's not just Bill Gates; he's the Bill Gates," Steve Ballmer told Newsweek magazine. "He founded the company; he's accumulated this wealth; he's got this foundation; he's got this fame. That's irreplaceable."
"Also, Bill grew up with every one of the technologies in this company. He's got more capacity to remember things than anybody I've ever known. It's unlikely we'll have anybody again who has that breadth."
Steve Ballmer is chief executive of Microsoft.
Craig Mundie
"I came here to do all the things non-PC. I remember talking with Bill. Bill said: 'Well, look, if we can just figure out how to write software for all these things, I'm sure there will be a way we can make money out of it.' He demonstrated in sort of a single interaction both this long-term view of things and the way he was willing to make big bets on intuition."
"I think that many of the things that the company has done have derived from a willingness to place big bets over the long term and, from my earliest days here, that was a hallmark of the way Bill thought about managing these new areas."
"I'm sort of a 'bet-on-people' person and, as an entrepreneur â€" someone who has started and run a business â€" my belief is that all of the leverage is on people; you want to pick and back the right people."
"I met Nathan Myhrvold and I met Bill Gates and, between them, I found that we shared a common enthusiasm for how technology would be able to help people in more ways."
"I was in the supercomputing business. So, you could say, to come from supercomputing to cars, televisions and wristwatches was about as far a departure as you could make. But, at the time, I personally believed that we always saw this trickle-down effect, where things that were at the limit of what computing could do quite quickly became commonplace â€" courtesy of the Moore's Law phenomena and other things."
"It was really the camaraderie around that view that I felt in those early meetings with Bill and Nathan, and the belief that we had to go find the answers, that no-one knew the answer â€" that was all I really needed to come here. So, we shook hands, and I came here as the general manager of a non-existent division to do non-PC computing and the rest is history, as they say."
Craig Mundie is Microsoft's chief research and strategy officer.
Mitch Kapor
"I think I met him, actually, even before Lotus... They were doing some sort of deal with Microsoft, and Bill was driving very fast in a sports car and showed up late to a meeting, and he hadn't had a shower... It was really his intensity that was the most notable characteristic."
"I think he just brought this combination of technical and business rigour, and joined them together in understanding how the fundamental trends in personal-computer software and hardware were going, in ways that he could use to just build an enormous business."
"They were focused and strategic and persistent, and that was really Microsoft at its best. At the worst, I think the kind of competition routinely strayed outside of fair territory, and there was kind of a win-at-all-costs mentality that made life extraordinarily difficult."
Mitch Kapor is founder of Lotus, and chairman of the Mozilla Foundation.
Bill Campbell
"Entrepreneurs are risk takers, and Bill Gates is no exception. For more than 30 years, he exemplified entrepreneurial spirit, innovation and philanthropy. He transformed the software industry and created a durable brand built on hard work and integrity â€" values that I personally admire. He will undoubtedly continue to amaze and inspire us with his charitable work."
Bill Campbell is chairman of Intuit.
CNET News.com's Charles Cooper, Martin LaMonica, Erica Ogg, Marguerite Reardon and Greg Sandoval contributed to this report.
