Gnome and KDE are both highly customisable - my KDE desktop looks nothing like Windows, or even anyone else's KDE desktop.
All mainstream Linux distors have package managers.
I have yet to find ANYTHING on windows or linux to equal some of Textpad's features
I looked at the list of features on the site, and I can see few features that Kate does not have, and many missing features (such as opening files over ssh) that Kate does have.
programming editors (best so far is Quanta but it's sooo slow!)
Quanta is an HTML editor. For programming there are very good text editors and a huge range of IDEs. LOTS of developers use Linux, so the solutions are definitely out there.
I like Klipper, but its too long since I have used Windows to compare it.
I have used only Linux for the past eight years, and would never switch back. My wife, seven year daughter, and my father all use Linux, and so do a few friends (including an accountant and a pre-school teacher, not just geeks).
I use Mandriva because of the control centre and overall polish, but it has a little less software in the repo than Ubuntu.
Good reasons not to use Linux:
1) Needing specific industry vertical software, and WINE or virtualisation does not work well. 2) Having spent years learnings Photoshop. 3) Serious gaming.
Solving most of other problems is a matter of finding the best app.