Gear upgrades before Raiding...

Cat form first... this considers that you are in T5 and badge gear only... people in T6 or greater gear might have better in any given slot already.

Head -
Mask of the Watcher - Heroic Oculus
Hood of the Furtive Assassin - Regular Halls of Lightning
Helm of Cheated Fate - Heroic Gundrak

Neck -
Necklace of Arcane Spheres - Heroic Violet Hold
Necklace of the Chrono-Lord - Regular CoT Stratholme

Shoulders-
Spaulders of the Careless Thief - Heroic Nexus only... pretty sure at least
Spaulders of Frozen Knives - Honored with Son's of Hodir. The quest chain They Took Our Men!, began by Gretchen Fizzlespark in K3 within The Storm Peaks, begins the path of reputation for the Sons of Hodir.
Ceremonial Pyre Mantle - Regular Utgarde Pinnacle

Back-
Centrifuge Core Cloak - Regular Oculus
Bloodbane Cloak - Quest The Fate of Bloodbane - might be a chain but isn't mentioned on wowhead
(I am leaving out 2 Heroic drop cloaks around the same DPS value because the Centrifuge is in a normal instance and better or on par with the Heroic drops.)

Chest-
Drake Rider's Tunic - Regular Utgarde Pinnacle. Period. End of story. Run this til it drops.

Wrist-
King's Square Bracers - Regular CoT Stratholme... drops in Heroic mode as well
Advanced Tooled-Leather Bands - Heroic Halls of Lightning

Hands-
Charged-Bolt Grips - Heroic Halls of Lightning (almost the best in slot, you really want these.)
Bile-Cured Gloves - Heroic CoT Stratholme
Handwraps of Preserved History - CoT Stratholme quest reward.
Sidestepping Handguards - Regular Oculus
Eviscerator's Gauntlets - These can be crafted if all else fails. Honestly the Eviscerator's set is a good place to start replacing more TBC gear.

Waist-
Batrider's Cord - Heroic Drak'Theron Keep
Sharp-Barbed Leather Belt - Heroic Utgarde Keep
Don Alejandro's Money Belt from Hyjal is still pretty good but if not look to Eviscerator's once again until something better comes along.

Legs-
Ravenous Leggings of the Furbolg - Heroic Utgarde Pinnacle
Mind-Expanding Leggings - Kirin Tor seems like a good faction to grind as a Feral Druid.
Eviscerator's Legguards - crafted and works until better comes along.

Feet-
Slag Footguards - Heroic Halls of Lightning (just run it until they fall)
Gorloc Muddy Footwraps - Heroic Gundrak
Eviscerator's Treads - Crafted and good... really good... unless you already had Footwraps of Wild Encroachment from TBC

Rings-
Band of the Kirin Tor - 8K gold... ugh
Stained-Glass Shard Ring - Zone drop in Heroic Ahn'kahet: The Old Kingdom
Bjarngrim Family Signet - Regular Halls of Lightning
Signet of Bridenbrad - Quest reward from Light Within the Darkness
I am going to stop here but needless to say there can be a lot of upgrades here both crafted and quested as well.

Trinkets-
Darkmoon Card: Greatness - probably going to cost you more than that ring I mentioned.
Meteorite Whetstone - Heroic Utgarde Pinnacle
Incisor Fragment - Heroic Drak'Theron
Darkmoon Card: Crusade - still decent and so is Bloodlust Brooch and the like...
Fezzik's Pocketwatch is behind the 2 mentioned above and even a little behind the Brewfest DPS trinket but barely.

Staff-
Jailer's Baton - Regular Violet hold
Hewn Sparring Quarterstaff - Regular Halls of Lightning
Stave of Shrouded Mysteries - Kirin Tor rep and good for Bear and Cat
Enraged Feral Staff - Heroic Utgarde Keep
Lightning Giant Staff - Heroic Halls of Lightning
Staff of Trickery - Heroic Violet Hold
5 of the top 6 staff's are from Naxx raiding... FYI

Idol-

Idol of the Ravenous Beast - 15 Emblem of Heroism