By life experience, I don't mean getting older. I mean the richness and variety of your experiences. My dad's always harped on this with me, about how I should get involved in everything I can ('"really? everything?" *evil grin*). The idea seems to be a) to have more subject matter about which to write, b) to be able to write about that subject matter with more realism, and c) to have more emotional experience and maturity which will theoretically lead to more mature writing. Fair enough.
Reading experience is, again, not just how much you read but the quality of what you read. Like, if you read enough brilliant stuff the brilliance will be absorbed through your eyeballs into the creative centres of your brain via psychical osmosis. The literary snob attitude (in the "how can you even think of writing in [genre] if you haven't read [classic author]?" vein) that some critics and established writers sport can be irksome at times, but there's truth to it--how can you know what's already been done or learn from how other writers handled certain plots/characters/settings/etc. if you don't read?
I'm all for both, I just have trouble balancing them and my writing. I think if I didn't have school and work (and I wasn't living at home), I'd be tempted to just write write write and a little reading on the side. In junior high and high school it was more like read read read and a good deal of writing on the side. Perhaps in a past life I was one of those mountain-dwelling hermits. Though sometimes it seems like there's so much I want to do and see, and so many books I really should read and absorb, and so many stories clamoring to get out of my brain--gah! I need a handy time-stopping device so I can have a little time to think without being aware of the sand slip-slip-slipping through the glass.
At the final count, I tend to err more on the reading side than the life side. The rest of you?