nc is useful. For example: if you have a disk image downloaded on computer A but want to write it to an SD card on computer B, you can run something like

user@B: nc -l 1234 | pv > /dev/$sdcard

And

user@A: nc B.local 1234 < /path/to/image.img

(I may have syntax messed up--also don't transfer sensitive information this way!)

Similarly, no need to store a compressed file if you're going to uncompress it as soon as you download it---just pipe wget or curl to tar or xz or whatever.

I once burnt a CD of a Linux ISO by wgeting directly to cdrecord. It was actually kinda useful because it was on a laptop that was running out of HD space. Luckily the University Internet was fast and the CD was successfully burnt :)