kidman, saving for the future is so underrated. Although I recommend against it...you can always cash out your 401k deferrals (with a penalty) if there is an emergency....but just make sure it is something like a health emergency, not an emergency need for a new car or an emergency gambling debt.
I tell people the right amount is between the maximum the employer will match (sometimes 3%, sometimes 5%, sometimes 0, etc.) and the most you can afford (there is a cap every year)