Singularity
Don't be late for the singularity. Once your mates get their brains uploaded, if you wait a week they'll have experienced years of virtual time, and will have entirely forgotten about you. And you won't know any of the in-jokes.
Don't be early, either. I expect we'll get the ability to upload brains (let's assume it's possible) well before we've invented computers that are independent and self-repairing enough that you'd trust them with your newly-immortal self. I can certainly see several singularities starting and burning themselves out almost immediately. Pick the wrong one and your best-case-scenario is to be stuck in obsolete and unreliable hardware for the rest of time.
Sure, the desktop revolution was inevitable. But that doesn't help the people who invested in Be. Or those that invested in Microsoft in 2001.