I'd miss the anonymous subroutines more than anything. Shoot, even when I'm using other languages that have them, I've only felt that Perl got 'em right. I'm lazy, I don't want to spell out "function" all the time.
The pseudo-random mixing and matching of arbitrarily nested data structures are an amazingly close second. Complex data is organized for you! You don't have to clean up or allocate them, or make about a bajillion typedefs t use them effectively!
"If you go on with this nuclear arms race, all you are going to do is make the rubble bounce" -- Winston Churchill