Well, the biggest upside is that there are basically 4 of us running a top 100 internet site, so we each get a lot of responsibility. Also, anything we do affects the lives of literally millions of people, which is pretty cool.
And yes, the warm fuzzies I get when see the reddit community do something awesome are what keep me coming back day after day. Knowing that in some small way, I helped facilitate that awesomeness.
You guys really do an exceptional job running the site, kudos for that (and yes, that includes the chocolate covered granola bars if you so wish). The community has really evolved into something pretty awesome.
We're not in it for the money, because the money isn't that great. Conde is a private company with no stock either.