I haven't picked a date yet but I will likely be relatively young when I pull the ripcord - late 30's or early 40's depending on how life plays out over the next 3-5 years.
With as much as 60 years of life still in me (I hope), I expect to semi-retire, rather than go for the full thing so early. I just don't have enough faith in any "Safe" withdrawal rate to risk my entire financial future for such a long period of time. My biggest worry is that 20+ years after retirement, once I've become essentially un-employable, I'll realize that my portfolio alone ain't gonna cut it. And then you'll see me working 40+ per week as a Wal-Mart greeter trying to make ends meet. Not how I like to envision my "golden years".
Instead I plan to retire from the 12+ hours a day I now give to MegaCorp to something a bit more leisurely. DW is currently self-employed as a freelance writer and is making a push into travel writing. Her schedule is her own and she takes only the projects she wants. The Internet and international cell phone service allow her to work from anywhere in the world. She's making a respectable living at it, too. I figure with my help she can cut her hours down to about 20 per week and still make enough to cover our day-to-day expenses. We'll then have the flexibility to go where we want and do what we want while still having some money coming in the door so we won't have to worry as much about what the market is doing to our portfolio.
Cheers