To be perfectly honest, I have heard so many claims and counter-claims about Area 51 I really don't know what to believe. I think secret technology (both domestic and foreign) may have been tested there but I think at some point it became a diversion for the same operations being conducted elsewhere.

The government conspiracy thing is bothersome to me. It seems there was a general decline in trust for the government as an aftermath of the Kennedy assassination and subsequent conspiracy theories. The trust level has slowly eroded ever since.
In my opinion, it is very difficult, perhaps impossible to sustain a conspiracy for very long. In addition, the level of clever resourcefulness required to perpretrate an elaborate conspiracy requires organizational and logistical skills I have never seen at any level of government. I tend to be very skeptical of government conspiracy claims.