I lived in Lake Havasu City for over a year, and I think I can safely say that I had the time of my life. It has a reputation as a party city, and I guess that reputation is deserved, but it has much more to offer than a fun getaway locale for a spring break vacation. Admittedly, that was the atmosphere that I was after when I first moved there, but that kind of lifestyle is only fun for so long.
In retrospect, the things that stand out to me the most are relatively simple, like getting a beer with my friends at the Mudshark Brewery, which has shockingly good food in addition to the expected (but appreciated) selection of beer on tap, or reading a book by the lake. It turns out that this place can be just as good for an easygoing, normal lifestyle as it is for an insane vacation hotspot. Housing prices are very reasonable, and there's almost always something to do. For better or worse, I was rarely bored.
I guess if there is any problem with it, it lies in it its isolation. Not that it's impossible to get anywhere; it isn't. It just isn't terribly convenient. Ironically, this was mostly an issue for me when tourists came into town. All of my favorite restaurants got crowded and loud. People were suddenly rude and entitled. I think I left for good because I felt that when push came to shove, everything was more for the visitors than it was for me, someone who had tentatively decided to settle down there and make a life. The summer heat didn't help.
It really is a heck of a good time, though.