Imaging Infra Red seekers are deadly indeed, but forget about the advanced AAMs for a second, the main threat is Strela and Stinger type launched missiles. The Stinger uses UV to distinguish the target from countermeasures. And advanced Strela types use optical contrast. So yes, they may have dual tracking systems. But the cheap and most common Strela-2 has a very basic IR seeker.
@ Shawn. Uhm, laser is more commonly used to guide weapons to static targets, at the least, slow-moving. Laser jammers are therefore fitted to surface ships for example, not to aircraft. Not to track moving aerial targets, at least I haven't read about it yet, anti-air missiles don't 'ride a beam'. Laser doesn't detect in itself, so even if you use laser you need something like IR, TV, Radar or an operator to use it for tracking. But well, maybe I am lagging behind.
@ Aviator. Chaff has been mentioned, don't underestimate it just because the material is so simple, then there's jamming of course. There are also various form of more sophisticated decoys than chaff. Towed decoy is often used to emit signals to jam enemy radar, breaking the radar lock, and/or become the target.