I started playing during summer 2011, Nasus was my first champion i ever played, he's really fun to play. I was working on my build whole time i play LoL.

And i think i found best one for him.

Things to do as Nasus:
- Farm,
- Farm,
- Farm,
- buy items,
- go back to farm,
- farm,
- kill everyone in teamfight.

My build is a little bit strange, but trust me - it works

Start with boots.

It will give you 3x hp pots, so you can stay longer on lane and speed to avoid skillshot.
No skillshots? Get doran blade/shield, then boots. Remember that you can buy 2 or 3, up to 4 dorans, it gives you nice health and damage boost.

Trinity Force

Everyone buys TriForce on Nasus. Enchanting Q, W, E and R. Expensive core item, but worth it.

2x Hextech Gunblade

It's strange, but actually it will give you a lot of healing during Teamfight. With passive, you arre going to have about 60 Life steal, so with 150 ad you will heal 90 per hit, combined with nice AS from TF is just too much imbalanced
And by using E and Q and R, you will heal with spell vamp. Seriously, in teamfights you will deal tons of damage and tons of healing, targeting you is bad situation for enemy, becouse ad carry can destroy all of enemy team. They can ingore you and your healing effect is useless, nut yoy will give a lot of pain to enemies.

Frozen Hearth

Mana to spam on lane and armor to ignore more damage from your opponent on lane or jungler

Force of Nature

A lot of Magic resist and regeneration, you,re unkillable now with your healt regen, Life steal and spell vamp.

Mercury's treads/ Tabi Ninja

depends on enemy, if magic damage heaby or a lot of cc, take mercury's treads. If Attack damage heavy, then pick up a tabi ninja.

I hope this build will let you pwn people and enjoy this awesome champion.
:D