i7-3770k with GTX 550 TI its not as powerfull in the gfx dept. but the cpu is a stunner.
it will max out diablo no problem but the real difference will be when you use the cpu for other things. as it offers roughly x2 the cpu horsepower per core than the fx6100
when it comes to things like photoshop and transcoding.
it really is a no brainer for this choice the 3770 will be a great jumping off point for upgrades in the future, while the 6100 will be an ok 1.
the best part is the ivy bridge system will give more power but cost less to run... quite a bit less over a year. maybe even as much as $30 per quarter. thats 120 over a year... which isnt a lot but it is a good enough difference to warrant serious consideration.