What's your budget? Compared to the 150 Euro 1090T, 180 Euros for the i5-2500K is reasonable considering the performance you get in exchange. So, if you're not totally determined to go with AMD for personal reasons, the 2500K and a Z68 or even a P67 board is the best performance for the money right now and in the foreseeable future. That is for gaming.
Since you also seem concerned about power I can tell you that an i5-2500K overclocked to 4.9GHz needs just under 20W more than an 1100T at stock 3.3 Ghz. Here: