I am almost 25 yrs old and I know I need to be planning now for my future. I am currently contributing 4% of my salary to my work 401k. They match $.70 of each $1 up to 15% of my pay. Right now, this is equating to about $3400/year total contributions. We also have a company pension, but I don't want to plan on that at all. Who knows if it will still be there when I retire and who knows if I'll be at this job long enough to get vested (7years - I have about 1 yr in now).
I am also paying $300/month on my car and about $120 on student loans. I am saving about $500/month and do not have any credit card debt, except the occasional charges which I normally pay off within 2 months max.
My parents always said to "pay myself first." This means that I should contribute as much as I possibly can to any retirement accounts. If your employer is willing to pay 70 cents on the dollar up to 15% of your salary, you really should consider bumping up your contributions. The more you contribute now will add up to a lot more over the long run.
Does your 401K company allow you to pick how the money is invested? If they do, you should think about doing an aggressive growth tactic. I'm not saying have all of your money go toward aggressive growth, but that's where a large portion of it should go. The key is to diversify and have your money working for you in a variety of ways. Since time is on your side, you can afford to be a little more aggressive and assume a little more risk.
The compounding interest adds up over time, so the more you contribute now, the more you'll have when you retire.
Check out the calculators I've provided below. They can help to paint a better picture. I would also recommend talking to a financial planner. I hope this helps, and remember, pay yourself first =).