Your choice sounds good - I like the Celeron over the Pentium 4 only because of better battery life. The Celeron uses less power, and a 2 gig Celeron is plenty fast for anything you will be doing. If you have plans to use your laptop at home, you might want to consider one that has a decent docking station. Also, you might want to think how it will sell down the road. Most all the Toshibas have good resale value. I assume the Dell products will be ok in that regard also.
I purchased one of those 256 meg USB flash storage units for my wife recently, and it is a very neat way to save important files, as well as being a convenient way to transfer data from one computer to another. It's a key fob sized unit that just plugs into the USB port, and appears to the computer as a removeable hard drive. My wife uses it to transfer data from the Mac at work that has no floppy to her Mac at home so she can do some work at home plus have a safe backup for her files. It works fine on my IBM - type PC also.
If you fly a lot you might want to consider the DVD/CDRW upgrade so you can have entertainment on the road.
Good luck with your purchase!
'82 300D/4.3L V6