When I wrote this answer the whole X and Y metagame was fairly new, as tiers hadn't been established at the time. I also never anticipated Talonflame to turn out to be as good as it is, so since this answer is outdated and just plain bad, allow me to rewrite it completely!
Stealth Rocks:
Once you get Stealth Rocks up on the field, the threat Talonflame possess is essentially cut in half as it loses 50% of it's maximum HP upon switching in. That and when you consider two of it's moves are recoil moves (Flare Blitz and Brave Bird), it's not going to be sweeping many Pokémon at all especially if it's holding a Life Orb. Talonflame is generally partnered with a Pokémon that can learn either Defog or Rapid Spin, so that it can clear away Stealth Rocks and Talonflame can switch in safely without losing 50% of it's maximum HP. So once you get rid of it's support then Talonflame becomes a lot more vulnerable, as Choice Band variants are essentially useless as they generally don't carry Roost due to being locked into it. Variants who carry Roost generally use it as soon as they switch in due to Talonflame losing 50% of it's maximum HP upon switching in. This leaves Talonflame open to being hit by Ground type moves, as when it uses Roost it loses it's Flying typing, thus becoming a pure Fire type and temporarily losing it's Ground type immunity.
Pokémon who resist Talonflame's STABs (generally Flare Blitz and Brave Bird) and can hit back twice as hard!
Pokémon who fall into this category include:
Physical Defensive Pokémon:
Pokémon who fall into this category include:
Other good counters:
(potentially*)
Passive Damage:
As I mentioned before Talonflame's two main moves are Flare Blitz and Brave Bird, both of which are recoil moves. Recoil moves are moves where the user receives damage equal to a certain amount of the damage dealt to the target, for Flare Blitz and Brave Bird this being 1/3. Because Talonflame loses 50% of it's maximum HP upon switching in with Stealth Rocks up on the field and because it sustains damage each time it's attack with one of it's STAB moves, you can use this to your advantage by letting it attack your Pokémon to rack up the damage. Of course this isn't recommended if you're Pokémon isn't holding a Rocky Helmet or hasn't got Rough Skin/Iron Barbs as it's Ability. This is why Garchomp with the Rough Skin Ability and Ferrothorn with the Iron Barbs Ability can both be used to potentially counter Talonflame (Garchomp more so as it can actually take a hit from Talonflame at maximum HP and strike back). If they were given a Rocket Helmet to hold the damage Talonflame would sustain would increase, as Talonflame would not only sustain damage from using one of it's STAB moves, but also from Rough Skin/Iron Barbs and the Rocky Helmet as well. Although Ferrothorn must sacrifice itself in order to take out Talonflame.