Perl6 - I'll believe it when i see it...in other words when it becomes a bit more common on servers, I'll learn some. perldoc should still work, or pick up a book, this forum, etc.
IPv6 - It's activated on most network devices but everyone is still only managing/maintaining only the old and still current scheme. Been hearing from 10 years ago about running out of ip address space. It's only a new addressing scheme and not exactly space science. The more practical implications like DNS server implementation configurations, munching on IPv6 strings in programs, and basically starting to manage that addressing space, will provide food for thought/work. Otherwise just thinking about it in a void is needless worry in my opinion.
HTML5 - Is just a step up from HTML4. You can learn the specific bits according to needs or preference. You can keep learning forever..but don't block yourself in by worrying about learning itself. No single person knows absolutely everything there is to know about HTML5 or whatever new stuff. If you do want to keep up to date, it takes a bit of time and willingness, and a good book or two to read at leasure.
Power Shell - If you need to be seen to use it then learn it. I much prefer the unix and equivalent cygwin capabilities.
I've met many people who decided that learning any more is too hard, some even barely out of school. I'm sure they'll get by in life and work in the whole scheme of things. However I choose to keep learning as a lifestyle decision. Most employers and employment agencies already decide for you anyway..even if you remain a quick learner.