Lots of good thoughts on here, but I'm not sure anyone has touched on the reality of what happened with Ananias and Sapphira. Consider that this is virtually the same sin as Achan in the conquering of the Promised Land.
Joshua 7, (NASB)
1 But the sons of Israel acted unfaithfully in regard to the things under the ban, for Achan, the son of Carmi, the son of Zabdi, the son of Zerah, from the tribe of Judah, took some of the things under the ban, therefore the anger of the LORD burned against the sons of Israel.
Peter gives away the key to understanding this corrupt pair's acts of sin.
Acts 5
3 But Peter said, "Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back some of the price of the land?"
Peter identified the issue as a spiritual battle, just as Achan's choice to withhold plunder from Israel collected during the battle for Shinar was a spiritual battle. That sin occurred early on in Joshua's ministry and leadership over Israel, and it needed to be nipped in the bud quickly, or it might become a plague on Israel. Achan brought Satan's battle against God for Israel into the tents of Israel. For his sin, Achan and his family were stoned to death, and his livestock, even his possessions, were buried under "a great heap of stones" (Joshua 7:24-26) in the Achor Valley.
Just as with Achan's punishment, Ananias and Sapphira received condemnation for entertaining Satan and bringing his battle against the gospel directly into the church. It was stern warning to the new covenant believers that they should be wary of their thoughts, words and actions in light of their responsibility to the believing community.
It holds no portent for today's church, given that we've gone two thousand years and such treachery and satanic influence has entered into the church countless times without such a remarkable and visible judgment being handed down from on high. But the fragility of the early church, as the fragility of early Israel, required a swift and credible response from God in order to establish a "signpost" event to discourage those who would do harm to the community before it really got a chance to be established.