I've installed dozens of Linux distributions side-by-side on my various laptops over the years and invariably I would be booting into the Windows OS of the day (XP, skipped Vista, happy with 7). Partly because of need to access some Windows-only software but also a comfort level. Even though 90% of my laptop use is for web/Internet. This coming from someone who spent his PhD doing everything in CDE (and having an Amiga at home).
But then I tried Jolicloud 1.0. It is based on Ubuntu but feels a lot more like the iPhone in presentation. Applications arrayed on a home screen. Application windows maximized with very little OS clutter. Web applications promoted to feel like full apps.
It boots so fast on my SSD Thinkpad X200 Tablet and it feels comfortable. Perhaps this is the Linux Desktop everyone is waiting for?
Of course, I'm waiting for them to rev the Ubuntu base they are working on so the two-point multi-touch and Wacom pen of the X200 Tablet actually work (they work in Ubuntu 10.04 and 10.10, if I recall correctly). That and supporting tethering to my iPhone (both of which work in Windows).