However, before we call Kindle Fire "the iPad killer", we need to point at the areas where the Fire will have trouble competing with the iPad.
1) The Andoid and Amazon app stores are still fairly anemic versus the iTunes store in terms of quality apps. While the total number of apps is similar (somewhere over 400,000 each), Apple still has about a 10X lead in the quality and number of paid apps.
2) The real advantages only work when the devices is connected to Amazon Content (optimized for the Silk browser and leveraging Amazon Cloud storage/caching). For all other content/services, the tablet may perform no better that any other low cost Android tablet.
3) This is not an enterprise device. And even though Apple with tell you the iPad is not designed for enterprises, it is taking the enterprise market by storm because of the ability to push-out, control and secure apps, access to 3G networks, and the ability to access a full suite of sensors the iPad-2 offers (front-back cameras, GPS, accel, etc.). The Kindle Fire does not have any of these sensors to support a broad range of enterprise use cases (like reporting quality issues in the field, providing location aware content push, or 2-way video collaboration).
So while the debate today is over which one will dominate the market, the real conversion should be around how the Fire may disrupt Apple's content play and pricing for consumers. The pressure to role out iCloud just got more intense as Amazon bundles in cloud storage for free with the Fire. But for now, the iPad and its look-alike Android challengers will be driving the enterprise opportunity until Kindle Fire offers some of the ket features and control large enterprises will require.