I am in the market for a new notebook.
I am not sure how the market for building your own notebook exists out there right now. I would like to build one if I can. If I can build one, what would I have to do to build one that has long battery life (5 to 7 hours)?
Right now I have a Toshiba laptop that runs for usually 1 hour and 1 hr. 15 mins. at best (a Celeron M). Is it realistic (and smart) to upgrade my laptop with new components, or should I just get a new one?
It would be nearly impossible to upgrade your machine, or more accurately you would be so limited in what you could upgrade that it really wouldn't be worth the time and money involved. As for building one, it is generally much more difficult to build your own than with a desktop. There are a few do-it-yourself machines, however. Battery life will also be affected by the components you select.
In order to recommend a machine, I would need to know what you would be using it for, what size range are you looking for (the bigger it is the more upgradeable), your price range, and whether or not you intend on upgrading the new machine in the future.