What percentage of my portfolio should I invest in gold or gold mining stocks?

I'm 40.

precious metals are often considered a safe haven in inflationary times. also with this recent trendy commodity boom, speculators and hedge funds have thrown billions into the markets, taking them to non-fundamental highs. commodity investing is highly speculative and in fact trades on basic supply/demand economics. the problem is that the average investor doesn't know what these figures are, so they have to rely on some broker to trade correctly for them. it's a big risk. my answer to you is that you should invest whatever percentage you don't mind losing. also, if it DOES happen to appreciate, start taking pieces of it out. there is an old saying in the commodity investment market: sometimes the bull, sometimes the bear, but never the hog.

I'm at 80% of total portfolio. Risky? hell yes but I understand what I own and why.

Depends on your portfolio size, risk profile, personal goals, etc...without knowing all that, I'll recommend 2-5%

2-3% (max., total). More important, do you have an "asset allocation"?

none. If you invest in things like gold or diamonds, then the terrorist win! Terrorists have difficulty transfering money because the US is doing a great job of freezing bank accounts worldwide. And since terrorists cannot just carry duffle bags of cash from country to country (since its an obvious giveaway they are up to no good) they resort to carry a block of gold or a handful of diamonds with them.

Trust me! The only reason gold or diamonds are worth anything is because people are buying them. Don't buy!!! and help stop global terrorism. The gold you didn't buy, may have just been enough to stop the India train bombings 2 days ago.