if you're doing a str build for melee attacks you should def get power attack - for a monk you def want wis pretty high, and if going for power attack str too, also dex for helping with AC and con for high hp - whoever said the monk was MAD!
probably worth looking at some monk class guides too for more details
My first suggestion when making a melee character for Giantslayer is don't plan on going toe to toe with the giants. They are going to be bigger, stronger, tougher, and hit a lot harder than you. One good full attack is all it will take for you to realize your mistake. Against everything else, you should be fine.
Hit and run tactics, my friend. Hit and Run. Spring attack, fly-by attack, or ride-by-attack are highly recommended, especially if you can use a summoned creature to eat the giant's AoO for the round before you rush in.
I did fine with a Nature Fang Druid that focused on melee, Gorum Divine Fighting Style, and Vital striking.