Don't overlook other ways to save for retirement. Cut back on spending. Go out to dinner less often. Forgo the new car. Cut back on your cable bill. Go to a BYOB instead of paying for over priced drinks. Buy in bulk. Change some of your groceries to generic brands. Shop around for gas. Plan your menu for the week after seeing what is on sale. Trim your cell phone bill. Make sure you turn off all lights in a room not being used. Turn your thermostat down a few degrees in the winter, and up a few degrees in the summer. Keep up on all maintenance on your house and auto to avoid major repair bills. On and on you can go.
If you can save and extra $10 twenty times a month, you could put an extra $2,400 a year into your retirement.
If at the age of 25 you put the extra $2400 a year into an IRA (excluding your 401k) and got a respectable average annual return of 6%, when you reach 65 that account would be worth $371,428.72. That would be in addition to what ever you have saved in your 401k.
I currently max out my 401k, and also put away money into a scottrade IRA account. YTD I am up 14%