I would go with either the Toshiba or a low-end Lenovo Thinkpad.
Dells are a mixed bag; some are good, some are trash. However, the tech support is abysmal either way.
Toshibas are very similar; however, with the exception of the god-awful hard drives (Toshiba-brand HDDs have failed on me every time), they're generally okay in quality, and the tech support is supposed to be less awful.
Lenovo's laptops are generally more expensive, and you get less power for your dollar. However, you also have excellent tech support, and quality; I know someone who on my reccomendation bought an R50E (700$), and it's been nothing but excellent.
My next laptop's going to be an IBM. (Admittedly, I'm looking for a Workpad Z50-essentially, a PalmPilot in a laptop's shell-but I don't need anything other than Word and maybe Internet Explorer anyway.)