There are a few questions you should answer.
1) What will "job = life" really get you at the end of 12 months? Most of my career has been at a company where heavy busting ass meant a raise of 5.5% versus 3.5% for cruising, a raise of 95% of target versus 85% of target and a few thousand dollars of company shares. So, you could bust your hump working an extra say, 2,000 hours to get an extra, say, $15,000 (all numbers are just examples). That's $7.50 an hour, about like working at McDonalds.
2) How do people really rise up the ladder? At the aforementioned company, who you have lunch with or have Thursday drinks with has a MUCH larger impact than job performance. Personally I started having more success (raises/bonuses/promotions) by paying attention to these other factors and worked less hours than when i was cranking out tons of hours and producing more.
3) How often does org structure change? You could bust your ass this year, impress the hell out of your boss but in 18 months if you have a reorg that sends your boss to manage QA and you're reporting to someone that knows nothing of your magic year, the capital you built up would be mostly for naught, save for whatever money you made from point 1) above.
Given my own experiences working for giant corporations, I would never make job = life. Maybe where you work is different. Others suggested making (not job) = life and I'll cast my vote that way.
