Ask HN: Multiple awesome work opportunities - advice?

So, I currently have a couple of amazing opportunities (that I'm incredibly thankful to have) and I'm hoping some fellow HN'ers who have been in this situation can give me some advice.

A few facts about me: - Under 25 - Engaged - 1 year-old son

I'm a senior-level front-end developer, mid-level Node.js developer, senior-level designer (UI & UX/web), and have a decent amount of auxiliary knowledge and experience (enough to be a successful freelancer before joining my current employer).

I'm happy with everything about my current employment but the pay, and it doesn't look like that's going to change soon.

I have been contracting with a startup in San Francisco for the past couple of months, with the intent of joining them full-time once they raise more funds. I live pretty far away from SF, so if I moved there it would be a big deal and I'd like to be there for a long time (at least 2-3 years). I'm worried about how much time I'd spend working at this company (I've been made to understand there will be a LOT of burning the midnight oil) but I also believe this company has serious potential.

My other opportunity is to co-found another development shop with a co-worker. We've worked closely and pair-programmed on several projects at my current job (with great results). We both have pretty sharp business acumen, and I'd consider us good friends. We plan on growing into a products company along the lines of 37Signals/JetBrains/Atlassian.

Both have decent risk profiles, but I'm confident that if either didn't work out I'd find a way to keep food on the table.

Just the act of writing this down has helped me clarify my thoughts, but I'd really appreciate any advice you guys/gals can give (and don't worry about my feelings - if I sound crazy, tell it like is).

Thanks a bunch!