archive.org (internet archive) --> see offline/old pages that is no longer online/available.

translate.google.com --> translate text, web pages and act as proxy =)

pastebin.com --> paste code

imageshack.us --> host images

sendspace.com --> upload files

filewatcher.com --> find files

whatismyip.com --> my ip

ipcalc --> calculate mask, wildcard mask, network address, min host, max host...

default_pass --> default passwords for network devices