American Eagles in Gold and Silver are popular; you can find them all over with a search for American Eagle Coins. Other countries make gold coins as well. You can also invest in mining companies, or in a precious metals mutual fund or in a gold/silver ETF. Stock brokers will steer you away from actually holding bullion/coins, as they won't make any money. If you have a place to safely store them (gun safe, safe deposit box, etc.) go for the coins/bullion. You can buy/sell them through a coin dealer. I like the ideal of holding the metal I paid for. If a market collapses, I'm not so sure that those stocks/bonds/ETF investments will come through on their promises. If they don't, what can you do about it? Think about how Enron, Charter, Tyco, and all those other firms walked away with investors' money. Hold the coins and bullion yourself.
To be honest, it might almost be too late to get into the market as this point. However, I have read lots of opinions that the precious metals market will continue to rise a lot for a while.