Wel, I've used Dell Latitudes since 1999 and prefer them to a desktop.
Some 'notebooks' are far too heavy to be used as laptops; however, don't forget that you can have a docking station with keyboard, mouse etc or use a wireless/USB keyboard and mouse if you prefer. I deliberately went for non-integrated CD-ROM or floppy drives to keep the weight down; the 'media base' is just clicked onto my Latitude x200 if I need to use a CD-ROM or floppy as normally I transfer dta using a USB stick.
My Latitude LT was too fragile really - the design of the power connector was very prone to damage in particular. I had a battle royal with Dell when one of their repairers destroyed the computer and received a brand new Latitude D400 with Office 2003 plus external CD-ROM drive and external floppy drive in compensation. It is now my back up as I use the excellent x200 for day-to-day use connected via WiFi to broadband. It has been 100% reliable; I managed to drive over it when my briefcase fell over as I was getting the car out of the garage but Dell had it fully repaired, fitted a new screen, checked it out fully and had it back to me within a couple of days all under warranty.
I would agree that a wireless-enabled laptop plus wireless modem/router linked by cable to your desktop would probably be your best option.
If you do buy a notebook, make sure you have a good warranty!