You aren't going to win many converts saying "Bitcoin is better than gold", but maybe try "Bitcoin is a great compliment to gold", which is true since it is very different, but still has the important features.
But
it is better than gold.

I am not saying that it is a better investment option right now, just that it is a better currency.
Any commodity is a potential currency. What made gold and silver excellent currencies are some inner features of such precious metals, that are not only shared by bitcoins, but improved.
If you have patience with automatic translations, I tried to explain it here:
http://tinyurl.com/38llgfqFreeMoney is right. Unfortunately, hard-money Austrian-economic libertarians are immediately critical of bitcoin when they find out that it is backed by "nothing"

! I myself think bitcoin is superior currency to gold (since gold cost money to store, insure, is difficult to move around as most travel hubs such as airports will detect it, and is not safe carrying around in your pocket on dangerous city streets, etc.). But you are better of trying to tell gold-bugs that bitcoin is a great *compliment* to gold, not a *replacement*, since bitcoin is great for trading online pseudonymously, but in the case of total war or any distastes that break internet connections, then gold (and general survival skills) are better long-term investments. For sure, don't tell them they should move all their assets from gold into bitcoin
