[m0nastic]

It might just be my OCD showing, but 'clear' is my number one by an order of magnitude.

next 20:

  177 ls
  167 cd
  122 brew
  120 vim
  119 cabal
  117 cindy (an alias for ssh'ing to my local dev box)
  115 sudo
  114 tmux
  111 man
  110 less
  110 openssl
  109 rm
  108 whois
  107 ghci
  107 lein
  106 ssh
   86 strings
   75 smbclient
   75 racket
   65 nc

[dpritchett]

I use ctrl+L a lot in my term. It clears.

[albemuth]

command + k on a mac, I don't even want to know how frequently I use that.

[nailer]

Control L works on Mac too.