I like Intel the most in every case, but at this time I would recommend the 8320 without thinking, due to :
1-It's an 8-core CPU, which gives you power in every task and longevity before you need an upgrade.
2-In case you ever considered OC , well ... (bingo) says it all .
3- Upgrade path-wise you can buy steamroller (AMD's upcoming chip) for the same MB you have because it's an AM3+ chip, intelon the other hand will force you to change the ENTIRE build if want to upgrade.
my vote goes to 8320 as its as good as the i5 in games at stock speeds and in the future it probably performs better than the i5! also in the future if you want to upgrade your cpu if you get the amd cpu you ll not have to purchase a new mobo but if you go with intel you ll have to!