"A Martian Odyssey" was the first "grown-up" story I ever read, a feat I still recall with a feeling of well-earned pride some 34 or so years later. Now 42 and never apostate, I nevertheless feel as if the field of SF is going through something of a renaissance right now. Writers like Kim Stanley Robinson, Peter Watts and Neal Stephenson (to name three off the top of my head) have me feeling like a kid again. Even the monthly arrival of Analog sees me engaged in a ritual kiss before I tear open its celophane wrapper.
And, er, for some reason I am single again. Go figure.