EDIT: whoops. sorry. missed out on it being a pre-built. if there's an i5+770/280x build for around that same price, take it. otherwise, if you're not confident building your own, may as well take it.
if you want improvements, assuming you're using FRAPS, recording has more to do with an HDD fully dedicated to storing the video. faster is better of course.
with the exception of a few games (Crysis 3 & BF4 large MP maps come to mind), Skyping while gaming should not be an issue in most cases. unless skype starts gaining more bloat anytime soon.
some graphs;