The ruling New Democracy clings to a narrow majority: 152 seats (50.6%) on 41.8% of the vote.
I still am not clear on the details of the electoral system, but by backwards induction from the result, it appears that the proportional seats are indeed calculated as if there were a 260-seat national district, with the additional 40 seats added on for the party with the nationwide plurality of the vote.
Via EuroTrib, the parties that made it into parliament have the following seat totals, vote percentages (and change in seats and votes from 2004):
ND (conservative) 152 41.84 % (-13 seats, -3.52%)
PASOK 102 (socialist) 38.10 % (-15, -2.45%)
KKE 22 (old school communist) 8.15 % (+10, +2,26%)
SYRIZA 14 (antineolib left – greens – radicals) 5.04 % (+8, +1.78%)
LAOS 10, 3.79 % (not in the 2004 parliament)
Those parties combine for 93.7% of the votes cast, leaving 6.3% to be wasted on parties falling below the 3% threshold.
ND’s 41.8% would thus be 44.6% of the above-threshold national vote. Give them the 40 seats they automatically get rewarded with just for having the vote plurality, and you get an expected seat total of 156, or 4 more than the ND appears actually to have won:
(.446 x 260) + 40 = 116 + 40 =156
I am not sure what proportional formula might be used for the above-threshold national allocation, but it actually appears to have slightly under-represented the leading party (before the addition of the bonus seats, that is).
As was widely reported as expected prior to the election, the various smaller parties (including the far right) did very well. But not well enough to deprive the incumbents of their less-than-deserved new term.
The EuroTrib post, linked above, has some really valuable background information on the campaign and the parties (posted by a Greek writer who notes he voted for SYRIZA, as your Orchardist no doubt would have, had he had the opportunity.)
See also the Greek Interior Ministry site with results (yes, in English!). The pages still show seats by district, so while it appears (as I noted above) that the overall result is calculated as if there were a 260-seat district, evidently the 260-seat PR portion remains a two-tier system.