Well STR will deliver more damage to your melee attacks.. so that is never bad to stock up on. Another way of doing it though is to stack up on as much STA as u can, your attack spells will deliver plenty of damage, and if u can have a ton of health, then you will just outlive anyone that is equal to you in DPS, or even more DPS. STA and AGI are great to have, for avoidance, power, and health.....
As for the weapon to use, use what gives u the best of what your looking for. Be it, the maximum STR for maximum short burst DPS.. or STA and AGI for longer fights with more power and Health....
chain armor the same way. Use that which gives u teh best stats for what your looking for.
WIS will give you resists, which are great too, dont forget about the resists. That helps out a lot on fights. If you can resist and avoid most attacks, and have huge HP... then there are few fights u will lose. my 2 cents