OK, a few you've opted to ignore in your "good" list:
- Denmark has the far-left Red-Green Alliance, 8% of the vote, 14/179 seats.
- Finland has the Left Alliance, 7% of the vote, 12/200 seats. In the 1990s they generally won more than 10% of the vote.
- Germany has Die Linke, descended from the old German Communist Party (yes, the ones who ran East Germany), 9% of the vote, 64/631 seats, 12% in 2009, the second largest party in several states, including leading the government in Thuringia.
- Ireland has a collection of far-left parties who formed the United Left Alliance at the last election, which won 3% of the vote and 5/166 seats in the last election. Sinn Fein (10%, 14/166, but currently polling at 20% or higher) also are part of the far-left group in the European Parliament.
- Latvia's Socialist Party is still an explicitly far-left Communist (with a capital C) party. Generally contests elections as part of broad left-wing coalitions rather than individually, but has 3/100 seats.
- Luxembourg has The Left party, 5% of the vote, 2/60 seats.
- Netherlands has the Socialist Party, but I would accept the argument that they've moved a bit to the right in recent years, but they still are part of the European far-left bloc. 10% of the vote, 15/150 seats (17% in 2006)
- Sweden has the Left Party, 6% of the vote, 21/349 seats.
- Slovenia has the United Left party, 6% of the vote, 6/90 seats.
With regards to the thread title i actually agree somewhat. I've often wondered if there's a correlation between unemployment and the performance of fringe parties.