Welcome to the discussion Santiago.
I lurked here from the time I started thinking about retirement, through when I started actually saving up, which was when I was around your age. I'm 44 now and have only started posting since I've been close enough to taste retirement. I've taken the semi-retirement route as well to be able to have my cake and eat it too.
Eighteen months ago, I resolved to never get a full-time permanent job again, but only had 2 months off this year (Jan 20-Mar 21) before I started another 2 1/2 month part-time contract 3 weeks ago. I'll be taking the summer off for sure and then will see where I go from there. Likely won't be working again in 2010 after July as long as the market stays on track. If it doesn't I'll be going back to work for a bit.
I think you're right in going for meaningful work. I haven't paid enough attention to that, and am paying the price for it. It's more important than the money, that's for sure.