I played almost 10 generations as an archer (former Justus_Caesar_of_Chaos), and tested some builds, really sticked with that 2:
21/18
Strength:21
Agility:18
One Handed:10
Archery:154
Weapon Master:6
Athletics:6
Power Strike:4 (or IF, I prefer PS)
Power Draw:7
18/21 (the best)
Strength:18
Agility:21
One Handed:50 (or 39)
Archery:159 (or 160)
Weapon Master:7
Athletics:7
Power Strike:3 (or IF, I prefer PS)
Power Draw:6
After more then 500 hours of archery I must say, agi is better, but 6 PD is essencial too (not really need much more, u decrease too much status for it) , so 18/21!
I used Rus Bow 90% of that time, and Tatar 50%, Bodkins 50% (all MW).