Originally Posted by texasone1
One of my all time favorite builds for nunu was all kinds of attack speed to enhance his passive no mana needed! This gives him massive sustain because he can eat at least one out of each wave of minions without much mana draining at all!
I find that I rarely run out of mana if I'm using my W to increase my attack speed. Just make sure you always use your E as your free spell since it eats up mana the fastest. You don't really need any additional attack speed since they buffed his passive.
edit - actually lemmie just post my Nunu build:
runes: attack speed reds, movespeed quints, armor yellows, MR blues
start boots + ward + pot
philo and HoG
boots 2 (usually get merc treads but CDR boots are ok too)
rylai's (I realize this is an expensive item for a jungler but it turns your slow into almost a snare and it makes you more tanky)
finish off with upgrading to reverie, upgrading to randuin's and banshee's veil