New AMD CPU's

Yea a fellow League of Legend. I carry =)

http://www.anandtech.com/bench/Product/53?vs=399

An AMD a-series processor would be better, in large part because you'd need to get some sort of graphics card with the used processor as well.

Similarly, an Intel sandy bridge pentium (g620) + cheap mobo + ram would be the same price as the used combo and also more powerful.

You probably want to compare these two basic options All prices approximate, re-using components helps:

Intel sandy bridge pentium ($70-90) (probably g620 or g850 w/dvd burner combo)
H61 mobo ($55) (I recommend the asrock h61m-vs if you get a discrete graphics card)
4 or 8 gb 1333mhz ram ($20-$35)
Video card ($70-120, currently there's a gigabyte 6770 for $85 AMIR on newegg, more powerful than the AMD a-series integrated graphics)
cheap case (I recommend bit fenix merc alpha at us.ncix.com) ($35)
cheap but quality psu (varies, I think this week I was recommending the rosewill green 530w) ($40)
DVD-burner ($17 or less with combo deal)
500gb 7200rpm HDD: ($75, HDDs generally cheaper on us.ncix.com than newegg)
Operating System ($100)

AMD a-series apu + mobo combo @ newegg ($125-165)
4gb 1600 or 1866mhz RAM ($24-40)
Video Card ($0 for basic APU performance good for MOBAs, $50 for the appropriate crossfire card that will probably provide near 6770 performance)
see above case, psu, burner, HDD, OS

I'd heavily advise in favor of the Intel sandy bridge pentium option, perhaps even upgrading to a g850 or so. This is not because that option is inherently superior to an AMD a-series setup for a budget computer, but because Diablo (like many Blizzard games) will probably benefit more from the faster per-core performance of the 2-core pentiums vs. the 4-core AMD processors. MMO results will likely vary. This article may help:
http://www.xbitlabs.com/articles/cpu/display/amd-a8-3870k.html
Edited by MisterFred - 3/25/12 at 1:36pm

Almost every single person will tell you Bulldozer (the FX series) is tragically flawed.

This is true.

Every person that tells you an I5 2500k/2600k is your best option:

Is wrong.

Phenom IIs have comparable performance in games and lower prices, plus none godly expensive motherboards.

Food for thought.

As far as I know, the APU's are kicking butt across the board, don't know, I don't use one.

If you have no budget go for the 2500k + Gtx 560 + SSD.

If you want to squeeze every dollar go for the Phenom II 965+ AMD 5770.

Both will give you similar performance. I don't suggest going the APU route unless you want to use it for a HTPC.

Get an A8 3870K and you WON'T need a graphics card for the game. I'm currently using my motherboards 4250 onboard for graphics as my 4770 just died...It's running the game in 1280x720 window with medium detail. The 3870K should max out the game I'm thinking.
http://www.newegg.com/Product/Product.aspx?Item=N82E16819106001
Look at the combos too.