Do you have an opportunity to try out the keyboards?

I have the 13.3" Dell E4300, which is in the same series as the E6400, but it's a lot lighter. I like my E4300, but I think the E6400 is on the heavy side, so I'd probably pick the Toshiba or Lenovo machine (though they aren't the lightest, either). The Toshiba has dedicated video memory, which can be good.