Sony DSLR-A580L VS Nikon D90 which one would you chose?

I want to get a new DSLR camera. I currently have a Sony Alpha a300 but want something better that can record video. So far my experience with Sony has been excellent but a lot of people has advised me to get a Nikon. These two are my finalists and therefore I would appreciate your feedback.

If you are invested in the Sony system, I would stay with Sony. Especially, if you're happy with it, there's no need to switch. I think a580 is a good camera and if you like to do video recording, the a580 has better capabilities for video.

The Sony can higher resolution video up to 1080i, has an external mic input and a flip out screen which the D90 lacks.

May I suggest you also take a good look at the Sony a65 or even the a77. These cameras give you continuous auto-focus in your videos, 1080p video recording at max 60/50fps which is the most out of any camera, an external mic input, manual controls and has a new three way tilt LCD screen (a77 only)