USB is greatly overused...  1.1 is particually bad...2.0's good, but I still prefer other methods of connecting peripherals.
For me, definetly PCMCIA.  However, since we moved my room around, I've been connecting using a usb wifi card on my desktop and it's been just fine.  I guess one good thing, though, about PCMCIA is that more is inside your laptop than say a USB doongle