Longer you mean, but I digress.
When choosing hardware I usually weigh performance, features, reported reliability, and efficiency higher than price (though price is important of course). Additional benefits (such as longer warranty) come as an extra bonus, and should not necessarily be a deciding factor.*
In my opinion the extra 2 years does not make a big difference. It has been my experience that every hard drive I've ever owned has lasted significantly longer than the average 3 year warranty period (I have drives over a decade old that still work just fine). In fact, I have given away more drives because I did not need them anymore than I have thrown out/destroyed drives because of failure.
Plus both 3 years and 5 years is a long LONG time in the computer world, by then platter drives for the average joe might be dying off with SSD taking center stage. Platter Drives might be 2-3 (or 5+ if Toshiba gets to the point of producing bit-patterned based drives at a consumer price) times the capacity for the same price, who knows.
I guess I'm just really lucky with my drives.
*A drive that runs cooler and more efficiently should in theory last longer, which is what I'm getting at.