Mutual Funds or ETFs?

[nokia1566]

What would be the best way to put 25k to use in the market? I am 18 and will be buying and holding for several years. I plan on adding 1000-2000 a week to my portfolio (so mutual funds seem like the best idea because of the costs of trading of ETFs). What mutual funds would you suggest for an 18 year old who can afford to take some risks but also wants to be able to sleep at night knowing the money is safe? Should I be going 80/20 in stocks/bonds or should it be more like 60/40 in the current questionable market? Thanks in advance.