Berserker's Greaves Bloodthirster Black Cleaver Warmog's Armor Last Whisper Infinity Edge/Ravenous Hydra
IE and Hydra depend on your preference. Mostly, they're more like your luxury items, since you already have a huge +AD and sustain in BT, with CDR, hp, and shred in BC.
Personally, I prefer Warmog's over GA nowadays, since GA got a huge nerf at the start of S3. And since you'll be soaking to team fights as a melee duelist, a grand of hp, together with a hefty amount of hp regen, helps you to tank at least enough damage to survive.
Personally, I like building her as a bruiser. Your damage is still enough to kill squishies in a relatively short period of time, and you can sustain yourself without worrying about dying all the time.
Mercs Frozen Mallet Atma Warmog Spirit Visage Zeke/Cleaver/Guardian/Banshee/ whatever your team needs
Of course, if you're in need of some damage and have a number of tanks, you can go fullcarry, but it's not recommended since you melt in seconds.
Greaves Infinity Edge Phantom Dancer Sword of the Divine Last Whisper Blood Thirster
Tiamat is, and always has been, a useless gimmick build on Fiora that's only good for her ult, and only in low Elo when enemies don't know to scatter in time.