Excellent post, I prefer Sun or BSD Unix to Linux as well. Dell won’t make a software play anytime soon though (if ever), the current battles are in GUI and portability where Linux scores the worst.
Linux is pretty portable, it's currently on at least x86, Itanium, SPARC, MIPS, Alpha, M68K, PowerPC, ARM, PA-RISC and mainframes. And unlike Microsoft, there's no central authority that can make support for Alpha and MIPS disappear.
As far as GUI and general usability, I tried Ubuntu like I said I would. Windows XP is still ahead. I would put it at "acceptable for the average consumer if he can't afford better."