Grumpy Curmudgeon gets shown the error of his ways/joys of being a parent by some kid(s) foisted on him is one of the older plot devices in Entertainment (see also: Annie), but that doesn't mean it's not still viable when executed well.
Which Despicable Me does.
This, folks, is how you do "Family Entertainment"; successfully juggling the needs of kids (fun, vibrant, fast moving), with those of Adults (subtle humour that flies over the kids heads and storytelling that doesn't make you want to run for the insulin injector) to create an end product with elements and characters relatable and enjoyable by both. DM covers both grounds in spades; with solid action sequences, slapstick that's well executed, a high paced story that's compelling without becoming saccharine, and more than a few bits for everyone in the room (including a killer Lehman's Brothers reference), that bring the fun right into the final credits*.
Well worth seeing and one of the better films of the summer so far.
* While I watched the film in 2D, so am not positioned to comment on the other elements in the film, it's readily apparent that the the credits also happen to be where the creators are really playing with the 3D - with a slowly building bit of perspective slapstick that's well worth sticking around to watch.