I have been asked this question a few times and asked myself the same question too. What is so special about Silver? Many analysts have reasons for and against and I suggest you do research for yourself in order to come to a conclusion that satisfies you but I will give you why I am am more of a Silver advocate instead of Gold.
1) Silver is consumed.
Silver is being consumed by electronics, CDs, mirrors, photography, and during the process of making plastics among others. Gold is used in some areas including electronics but silver is a better conductor.
2) Smaller supply.
There is roughly 8 Billion Ounces   of Gold. There is about 1 Billion Ounces  of Silver. (by the way, ref #2 is a great study). No one knows for sure but 8:1 ratio of GOLD:SILVER supply would indicate that the white metal is extremely undervalued.
Because of the current price (about $27) at the moment, there is a huge upside potential. The GOLD:SILVER price ratio is currently 50:1. Even if it got closer to 8:1 and went 30:1 price ratio. It still looks like $45.13. Still pretty good gains!
You can see the places I buy from here.