LR has always required external programs like Photoshop for more advanced editing techniques. While that is still true for multi-layer compositing and individual pixel bending, the gap continues to shrink. User demands for features such as the ability to create panoramas and High Dynamic Range (HDR) images directly have finally been met. There seems to be broad community consensus that they did a really good job on the panoramas, but that HDR is just so-so. One of the key technologies Adobe finally took advantage in modern computers was the computational power found on the video cards themselves. These specialized Graphic Processing Units (GPU) are designed to handle the insane level of demand for modern video games. Previously, LR was just too slow to handle the massive computations required for edge matching and the masking required for seamless blending of big images.
The processes for both Panos and HDRs are pretty straightforward.
Simply select the images you want to use and either from the Photo>>Photomerge Panorama.
It opens up a new panel allowing you to choose what kind of perspective you want. Normally, you just want to leave it alone. One additional useful feature is the auto crop, which will trim off any missing pixels.
From there you can go back in and conduct any additional editing as it retains all of the .DNG information from the original images.
For example, you can take your image into OnOne and apply one of my favorite effects- the Tilt-shift perspective. I like how it makes the image look like a model.
For HDR images the process is exactly the same.
It is important to note that the merged image now has the full 32bit depth. Nifty eh? Now go play with your images.