and that is comparing the i5 2500k to the fx 8150. i5 2500k is only $220 vs the $250 for the 8150. But of course you could get the cheaper fx 8120 for only $190 and still is 8 core.
also i5 has 4 strong cores while the 8150/8120 has 8 weaker ones. Though if you're into OC you can get the 8150 to about 5Ghz!
Considering the X6 1100T, FX 8150 and FX 8120 are priced to compete with the Intel i5 offerings and they do that extremely well, they cut the balance between gamer and professional setups, giving you a lot of features for a reasonable price.
What is know for certain is that the i5 2500(k)/2400 per core will beat all the AMD high end chips, but in multithreaded applications and high thread counts all the AMD high end chips by and large beat the i5's, it is a matter of what do you need the system for. Personally there is nothing wrong with the experience offered by the FX range chips, the improved memory controller makes it more viable over the old Thuban while it offers high enough frame rates to not be noticeable in single thread crunch.
I have a 2500K rig and a Thuban and in high thread counts the Thuban is faster, as to how many threads you really need in your apps is debatable but the FX 8120 is a very feasible option in this regard.
Give it serious consideration, AMD chips are not as bad as the myopic reviews it receives. I also in no way say it is faultless, it is just balanced with the option of multitasking function.
A friend of mine has used 3ds max, Maya, photoshop & other apps. in 1090t @stock & a i7 2600 as well. According to him, the performance difference isn't as large as the price.
Those multicore software products would make good use of the 6/8 cores of the thuban/bulldozer.
But if you have no budget limits, then the i7 2600k should be your choice.
Having said that, there are a couple other things to keep in mind:
1. It seems like you're largely considering a system for professional use, overclocking a professional system as it if it were a toy is not very professional, although it is a quick and dirty solution.
2. FX Bulldozers get very power hungry under overclocking conditions.
3. The FX-8150 is the SAME CPU as the FX-8120 only its clocked higher, meaning, you overclock the 8120 you have yourself an 8150 for a cheaper price.
I'm not going to get into an argument with people, as it seems the groundwork has already taken root in this thread for a flame war.