Whether the i7 is worth the extra money depends primarily on your anticipated work load. If you are looking to use your computer for gaming along with web surfing, and other light duties then the i5 is probably your best choice. Most modern games are unable to use the extra threads on the i7 so there is little difference in performance between the two chips. The i7 is a better choice if you are planning to do moderate to heavy levels of video editing or if you are a student needing to run design software like AutoCAD.