I have a (relatively small) Thinkpad (x60t) and a HP 2133 netbook. I take the netbook on trips where I mostly expect to be doing email and surfing, but no significant (software development) work. In addition to having less to carry around, the smaller form-factor also means that it generally fits into every hotel room safe. And in locations where I just don't have access to a safe I don't risk having my much more expensive Thinkpad disappear.