The best warriors & weapons to have would be the very best you can get - I started to get rid of excess weapons etc that were costing me an income and not worth much on the att/def side - and replacing them with the top ones available - just keep enough adventure weapons to qualify for later quests. I'm sure others will have different ideas - but I hope it helps
I don't know which one is it: Royal Hersir Cost: 200,000 Attack: +16 Defense: +15 Upkeep: -16,000 Hel Minion Cost: 300,000 Attack: +20 Defense: +17 Upkeep: -20,000 Njord Warlord Cost: 400,000 Attack: +22 Defense: +20 Upkeep: -25,000