You can now use Adobe Camera Raw as a filter, which means if you forget to do something in Camera Raw you don't have to close the file and reopen it. So to correct the perspective in the following Photograph I turned the layer into a smart object (makes edits non destructive) and clicked on the Camera Raw filter.
Before the Camera Raw filter is selected, you can see the image is not aligned properly due to no monopod or tripod being used.
![](http://i41.photobucket.com/albums/e266/tapzilla2k/wonkyimage1_zps2d03bef9.jpg)
With the grid turned on before I use the manual lens correction tools to correct the perspective -
![](http://i41.photobucket.com/albums/e266/tapzilla2k/before_zps8d764c05.jpg)
With the perspective corrected -
![](http://i41.photobucket.com/albums/e266/tapzilla2k/after_zps3200d035.jpg)
Now I could do that with the straighten tool in Lightroom, however it's a manual tool so you have to be careful about where you draw the line.
This makes it a lot easier and saves time in the post processing workflow.