The concepts (OO, Hashrefs etc etc etc) will still be there, even if the syntax will change a bit. The challenging part of learning to code is not learning syntax, but learning the concepts - and when (not) to use them.

The changes when porting from perl 5 to perl 6 will be superficial. The real new stuff will just be new - you won't have to 'unlearn' it, just learn it when it comes.

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.
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I think there'll be more overlap than you think. Your Perl 5 knowledge will serve you well when you pick up Perl 6. I think knowing more Perl 5 will make the transition easier, not harder.

For instance, the syntax of hash refs may change from $h->{foo} to $h.{foo} (I think ;-) but not the fundamental notions behind hash refs. Similarly, becoming better at Perl 5 OO programming should directly improve your Perl 6 OO programming. The fundamental concepts won't change, only the details.

That said, it's also true that some areas will change more than others. If you haven't picked up formats, for instance, you may want to wait until the appropriate apocalypse. XSUB programming is another area whose changes are unclear. But overall, I'd recommend to dive right in, and plan for the transition only when you feel the need.

-><- -><- -><- -><- -><-
All things are Perfect
    To every last Flaw
    And bound in accord
         With Eris's Law
 - HBT; The Book of Advice, 1:7

You're not going to regret it.

Slightly less flippantly, anything you do to learn about your craft is worth doing; you can pick up really useful and important stuff in the weirdest of places. Admittedly, Dylan's not going to do much for your Perl programming, but maybe he'll do something for your understanding of human nature and the rest of the world around you. Which is no bad thing. Or maybe he won't. Ah well, at least the journey was interesting.

Perl 6 sounds like it's still a fair way off, and 5 will be around for a long time after 6 arrives, so continuing to learn Perl 5 is definately not a lost cause. That said, I don't know of anyone who doesn't have additional things to learn as well.

Using myself as an example, I feel I have a decent grasp of Perl 5 basics. I still don't know 94 ways to use unpack, and don't intend to spend time learning them anytime soon. This isn't to say that I wouldn't value that knowledge, only that there are other areas I'd rather learn more about first.

I can quickly look up most parts of Perl 5 that I don't understand very well as I need them. As for broader concepts such as programming theory, I believe learning other languages contributes more to my understanding than learning Perl in greater detail would.

So, as I see it, my current level of Perl knowledge is good enough that learning Perl 5 isn't my highest priority anymore. This may be different for you depending on how extensively you use Perl, how well you know it, and what other areas you're interested in learning more about.