I'm looking forward to Perl 6, but I think I should start a lottery on how many years it will be before anything is released.
The optional availability of typing, especially with parameters, will be quickly and obviously useful. Personally, I like regexp being re-cast into something more powerful that lex/yacc. Continuations, directly supporting co-routines. Not to mention being able to select different languages for different components, where their relative benefits fit best.
It will take a while for people to change over for anything serious or commercial, but it should make for interesting SoPW.