I understand that you are looking for recommendations about 2 Intel processors.
In this particular case I would suggest the i7-2860, since this processor support 10 physical cores plus 10 logical cores, for a total of 20 cores, while the other processors supports only a total of 12 cores (6 physical and 6 logical).
Please check the following comparison chart:
Just keep in mind that if you will need a lot more than 32 GB RAM, you might need to use the Intel® Xeon® processor X5675 since this one supports up to 288 GB RAM, while the i7-2860 supports only 32 GB RAM per CPU.
Good point about cores, I just see the 3 GHz and think POWER . It's hard to balance many cores/ lower MHz vs higher GHz / lower core count- Roland