My current Macbook Pro mid 2012 non-retina is i5 2.5Ghz 1280x800 display.
The new Macbook pro 2015 model has i5 2.7Ghz 2560x1600.
I only browse web and watch videos. The main difference is the video quality, is it huge difference watching videos? also i dont do gaming. is it worth upgrading just for retinia display it for extra $1000?
Yes... you should see a very noticeable difference in video quality...but that also depends on the original quality of the videos you watch. Assuming Macs scale well...I believe they do...you should be able to get videos to look roughly the same size on each. The difference, however, will be the quality. If you watch something recorded in FHD+ it will look much crisper on the Retina display. I notice a huge difference between FHD and QHD...so you should see even more. Whether that is worth the extra money is your call. In addition to the screen resolution, you should also see better battery life and performance.