Almost 3 years ago, I decided do ditch my old PII Celeron and buy a new HP Pavilion Pentium 4. The Pavilion had Windows XP preloaded and it lasted about a week. Since that week, it has been running Ubuntu and I never re-installed it. I have been dist-upgrading the machine from Breezy (ah, those were the days) to Dapper. Since I like having a stable machine, instead of feature rich, "running latest versions of everything" machine, I've been using Dapper until yesterday.
Since the early days of Linux having a "desktop environment", I have always been a big fan of Gnome. It looked right and has always served my needs. As a java developer, I use Gnome as the preferred desktop environment at work too. Using Gnome, or any desktop environment, hours and hours in a row, enables you to discover the less pleasant parts of it. So, after a year of developing on a Gnome desktop, I have come to dislike it.
A few months ago, youtube was flooded with short demos on the new, upcoming, KDE 4 desktop environment. There were also a lot of demos showing Combiz, Beryl and later Compiz Fusion, but I never got very impressed with those. The KDE 4 demos impressed me though and I came to learn more about KDE and its applications. Gutsy was the first Ubuntu release providing a KDE 4 live CD, it was love at first sight :)
In my opinion, KDE has done a good job looking at the Mac OS X user interface, features and applications. I have also the impression that these applications written for the KDE desktop are more feature complete and mature than similar applications for the Gnome desktop. For me, it seems the Gnome desktop is a collection of small, feature incomplete, immature, applications. If, for example, you're looking for a "Total Commander" clone for Linux, you have the choice of 2 (maybe more) clones available for Gnome. These "Total Commander" clones for Gnome are less feature complete, then lets say Krusader. So I was using Krusader on my Gnome desktop, amongst other KDE applications as Amarok and K3B.
I was determined when the next LTS would arrive, I was going to switch to the KDE desktop environment. Unfortunately, from what I heard and read on the Internet, Kubuntu 8.04 won't be an LTS, since its primary focus will be KDE 4, which is considered not stable.
Indeed, KDE 4 is far from stable, but it works and it looks and feels right. This is the desktop environment for Linux I have been waiting for. The KDE developers still have a long road to go, since most applications still aren't ported yet from KDE 3.x. Integration of GTK applications, such as Firefox or Thunderbird, also need more work.
I don't want to start a desktop war here. The cool thing about Linux is that _you_ can choose whatever desktop environment or window manager you want. I chose KDE 4 :)