Given the BSD foundation, I just treat my powerbook as a unix system (which it is). I installed the X-windows development kit so I could use Tk, I use CPAN to install modules whenever I feel like it (though as suggested above, sometimes this takes a little extra effort), I edit my perl scripts with emacs, I NFS-mount the terabyte server volumes when I'm at the office, and while I use xterm a lot for day-to-day command-line stuff, I'm really loving the quartz-native "Terminal" with its nifty transparency feature and full unicode support (including bidirectional display for handling right-to-left text data -- amazing stuff).

I avoid anything that's Apple-centric, because for most of the perl stuff I do, I'd like it to work equally well on any other unix box (or even M$-windows, if absolutely necessary).