Thanks guys for making my decision even more difficult No, seriously, on my current computer, which by the way is now behaving after I've improved CPU's heat dissipation, playing HD video over flash is a PITA. I'm not much of a gamer nor planning to do video edit, other than perhaps a few minutes of instruction videos. No Bluray, no 3D in a midterm future. So knowing that a 6000 series GPU can make things easier for the CPU watching the Berliner Philharmoniker online is very interesting. One more reason to see what's the new iMac mounting.
I've checked Dell and a 27" display alone is close to 1000 euros, so building a windows computer with the same performance as the i3 iMac, would make the overall cost about the same, and a "serious gamer" computer with such display would be about the same as a quad iMac with SSD plus HDD.
So unless this computer definitely crashes and I can't live much time with the MBP as the only computer, I'll wait to see what the new iMacs have to offer. Hopefully that won't be more than a few weeks.