Charles: One of the better ones, although perhaps not as awesome as the decisions to:

study for my master's degree at the University of Toronto, which was the reason I was in Canada and how I ended up being sponsored by the IBM Center for Advanced Studies
conquer my intimidation and write an article for the Linux Journal, which is what W- recognized my name from
help a friend by joining the judges for a LEGO competition, which is how I met W-
invite W- to watch Wicked, which resulted in a reciprocal invitation to watch community opera months later
rent my own apartment and ask W- to help me with the paperwork - he was easily the most respectable of my friends, I think
confess my feelings for W- when he hinted about his, which meant planning and mindmapping to explore the ramifications before I said anything
cohabit despite the protests and worries of family
start making long-term plans despite my initial apprehensions about relationships and commitments

There was considerably more uncertainty and sacrifice (personal and relational) in the decision to study at the University of Toronto than in the decision to formalize our relationship with paperwork. Cohabiting was a much bigger gamble than picking a date and hoping everyone's visas arrived in time (we rescheduled to accommodate paperwork, actually). Decision-wise, marrying W- was easy. There wasn't a lot of risk in it. The benefits and consequences were well-understood, and the process was also well-documented.

If I had to pick one decision that was tough and really worth it, I'd say it was the decision to confess and start a formal relationship with W-. That wasn't easy at all. The odds were stacked against it. My studies were wrapping up, and I was supposed to return to family and friends back in the Philippines. He's a fair bit older than I am, so my best-case scenario is still losing the person I love relatively early in my life. He has a daughter, so family life was going to be different. Shared custody with his ex-wife meant that I'd be signing up to stay in Canada, which meant needing work permits, permanent residency papers, and the ability to not just survive winter but deal well with it. I had recently finished another relationship, so there was a chance that rebound was messing with my brain. There were a lot of things going against it. Plus sides? I knew he was kind, thoughtful, good at communication, and a whole host of other good things besides. After I mapped it all out, I decided that it was still worth it, and I wrote him a letter. It's been more than awesome since.

It's all a matter of priorities. I like my work, I do excellent work, but if I ever had to choose between my current job and my personal or marital happiness, I'd pick happiness every time. (And I've made tough decisions like this already, such as staying in Canada instead of moving back to the Philippines.) I can always find or create another amazing opportunity, so work is non-scary. I'm easy-going and good at being happy, so personal happiness is non-scary. Relationships require other people's input and they benefit from investments of time and energy, so they get more weight when I make decisions.