If you are looking at 15–16” then your tastes are different from mine, so lets see how different.
What sort of battery life do you want?
What do you plan to really do with it? Just surfing and watching videos, or are you planning to use it for hardcore gaming, video editing, etcetera? (Hint – that sort of stuff generally requires a laptop that sucks the battery down in half the time as a slower, more basic model.)
What color do you prefer? No joke; Toshiba offers many of their models in different colors.
Toshiba does have a laptop finder to help out, but you have to know what you really want. And some models are completely configurable too, so I really need to know what you are looking for to help you out much.
As previously stated elsewhere, you want to stick with Intel CPUs. You want at least 3GB of RAM to keep things snappy. I would not pay for MS Office or Norton anti-virus, as I use freeware equivalents of both that are actually superior. Whether or not you need an optical drive is up to you.