I think D3 is a more or less decent game through the first playthrough, even though I found it a bit easy. If you played it like a game you weren't going to try to complete through the additional playthroughs - Nightmare. Hell and the infamous Inferno - it's one with relatively decent story (I say relatively because we are, after all, talking Diablo and Blizzard devs here) and very nice graphics.
As you play through it again though, at the higher levels, the game's fundamental flaws show up more and more. Your character running away from those mobs about to kill you can stop to pick something up off the ground you hadn't intended (since the all-encompassing action button, the left mouse click, works for movement as well as everything else), allowing the mobs to catch you, or more likely the AoE damage they are spewing out to kill you because you couldn't get away fast enough.
Click-to-move is fine, and having a single action button works for most games, but tying these things together makes for a very frustrating experience at times, in a game the very definition of "challenging fight" IS frustrating experience; it is nothing more than a continual upgrade of AoE tactics that you have to survive again and again, all while being CC'd* in some way to prevent you from getting away from the AoE. This is why I stopped calling the game a good one with flaws, and started calling it a badly designed game with some good elements.
So, yeah, played as a once-through, it's worth $60, in my opinion, but to tell the truth I hate it so much at this point I don't want to recommend it even that much. It's just a bad game once things get to a decent level of challenge, then the poorly designed controls whip your hiney more than anything else. It's not impossible to get all the way through Inferno, and I can't help but admire the few who are able to deal with the game's control shortcomings and lack of intelligent design in making challenging fights to get all the way through the last level playthrough (Inferno). It's a lesson in "frustration management", a course in which few are up to the challenge.
* CC'd - for those not familiar, "CC" is short for "Crowd Control", and it comes from MMORPGs. Originally, it meant a spell or ability a player could use on a mob to take it out of a fight in some way - freeze it in place, stun it, etc. Now it stands for any type of effect that causes a mob or player to lose ability to move normally. "CC'd", or "Crowd Controlled" in D3 means being frozen on place, blocked by magic walls, that kind of thing, and the higher the level the more of these kinds of movement-impairing attacks happen. You can be stopped from moving several times, stacked on top of each other so you can't take a step in between attacks, have walls built entirely around you (you can even get stuck in a single wall that's cast on top of you) - as I say, "Frustration" with a capital "F".