I'd like opinions on Vanguard's 500 fund.?

For a long term forget-about-it fund.

It is ok for that purpose, provided you do not put all of your assets into it. No more than 25%. The reason is that the fund is heavily weighted towards large cap U S stocks. You need to be more diversified than that to provide the best return with the least risk.

Also pick a good foreign developed markets index fund such as EFA, a small cap index fund such as IWM, a mid cap index fund such as IJH, and quite possibly a emerging markets index fund such as EEM or FXI.

Maybe 25% in 500 fund
20% in EFA
20% in IWM
20% in IJH
5% in EEM or FXI
10% in money market.

Good choice based on low management fees and solid, but more or less index tracking, results.

This is a very good fund, and the management fees are very low.

Good idea - low expense ratio and smart way to invest. But I prefer the Spiders (symbol SPY). It represents the same index but even lower expenses and trades like a stock.

Benefits:
Lower expenses - you keep more of your own money and don't pay Vanguard some of your earnings. The small difference will just compound year after year the longer you hold it and eventually represent a big difference in your performance.
Trades like stock - Lower commissions (if traded online) and you can get in and out during the day. Price might not be what you saw earlier in the day!

With Vanguard you place your order to buy or sell and are filled at the closing price that day.

It is a very good fund But i like the Equity Income fund better.

I prefer Vanguard's Growth and Income fund. It is the 500 fund "tweaked" a bit by computers to discard the worst of the 500's companies. Therefore it usually has a better long term record than the 500 fund.