I am in an indecisive factor having to decide which funds should I enroll in Vanguard. The least risk level I see is investing on Vanguard Federal Money Market Fund, but I would want to know from people who might have already invested on some other with higher risks, more gains may be? The company will match 50 percent of the 401(k) contribute up to 6 percent of the salary.

Suggest or give me your thoughts on long term savings. thanks

Investment is very personal, it depends on RISK LEVEL and PERSONAL ATTITUDE!

If I were you I would look at INDEX FUND (VFINX) as well as Inflation Protected Fund (VIPSX).
VFINX-75%
VIPSX-25% (contribution level is based on my personal risk averse nature)

goto www.morningstar.com and do some research on the funds I mentioned.

things to look for
1. Expense ratio (the money the fund manager will take every year from your investment) [less the better]
2. Growth Since Inception.[more the better]
3. Risk Level. [high risk doesn't always mean high gain]
4. LOOK FOR WHY I RECOMMEND YOU THESE TWO FUNDS.

I'm sure if you do your own  research you'll know why I recommended you these TWO funds....(hope you'll find more too).

[don't naively rely on my advise, as I am not YET qualified to be a FINANCIAL ADVISER]
 

have you considered reading this before.

http://articles.moneycentral.msn.com/Investing/MutualFunds/the-best-vanguard-funds-for-a-401k.aspx