I have bought some gold at various points. I really seem to gravitate to US circulation gold (not modern US Mint bullion gold). I find it fun to put collections together.
However, I generally buy silver. It has a lower entry cost and a more volatile market that seems to make it easier to buy at troughs in the price. Just in the last year it has had two pretty good sized corrections. I generally buy locally for the convenience. Kearney Coin Center (http://kearneycoincenter.com/) is the local shop I frequent. They don't seem to have a lot online but the guy there is super friendly.