So what does it mean? If the surveys are right, and they all seem to agree, then just off the top of my head:

1) Zap has very close to an absolute majority, and he has more of a mandate than he did in his first term.
2) Rajoy will have to step down as PP leader, perhaps not immediately, but they need a new candidate for the next election.
3) The two leading candidates to replace Rajoy have to be Alberto Ruiz-Gallardón and Esperanza Aguirre.
4) I don't think Zap is going to do anything particularly different than he did in his first term.
5) The PP strategy of confrontation obviously did not work.
6) Neither the debates nor the murder of Isaías Carrasco had much effect on the voters.
7) The turnout was nowhere near low enough to help out the PP.
8) The Communists got completely destroyed.
8a) How much you want to bet that most of the Communist voters went over to Zap because they're so angry at the PP?
9) CiU did pretty well, and if Zap gets below about 170 seats, he'll have to cut a deal with them. The PNV did pretty well too, so a good showing by the comparatively moderate regional nationalists.
10) The more radical regional nationalist parties, ERC and the BNG, got stomped.
11) Zap's not going to negotiate with ETA any more no matter what happens.
12) I bet he doesn't keep most of his promises, though he's going to have to carry through on the €400 tax rebate.