get the samsung as it includes i7, blu ray drive and a superior screen than dell. samsung one has a higher resolution ( 1600x900) than the dell (1366x768) with more brightness ( dell screens are comparatively dark ( i have one )). the price difference however may be an issue in which case i suggest you go for the 5521 which also has a ULV processor which should give you excellent battery life. this is keeping in mind of course that you do not game.
Don't forget the
JBL speakers with sub woofers. They are really good. Much better than Skullcandy speakers of Dell & Beats audio of HP. Only JBL speakers(w/o sub woofers) of Y500 comes close to its quality(but still behind)
I would say, just get S04IN or for blu-ray S06IN(if u want to buy blu-ray movies)