Soc-dems did their poorest election since March 27th 1914 last time around, but they are still the biggest party with 8,8% more than the second biggest party. Most of those who migrated to the liberal alliance in 2006 will probably go back to soc-dems, and the rest will be split up in a wide range. I hope I'm wrong, but that seems more likely than anything else at this point.
Results for the Swedish Riksdag - Wikipedia
Abbreviations:
s = social democrats
fp = people's party (not at all what it sounds like; formed by fringe christians)
m = moderate coalition party (former right wing party)
c = center party (former agricultural union)
v = left wing party (former communists)
sp = socialist party
kd = christian democrats
mp= environmental party ("greens")
nyd= new democracy
sd = sweden democrats (assimilationists)
övr.= other
delt.= participation
What I call the "liberal alliance" was officially named "Alliance for Sweden" and consists of c, kd, m and fp.