If you use the community version I would recommend to use WildFly 8.0.0.Final. It is the further development as JBossAS7.x was renamed to WildFly.
All further fixes and enhancements will go into that project.
If you mean with "JBoss AS6" the community project you should not use it as it is an older branch which is not longer used. If you start here you need to migrate to AS7 or WildFly later.
If you meant "EAP6" this is the Enterprise version of JBossAS7 and you need a subscription if you try to run with it in production (see https://access.redhat.com/home for more details)