Notebooks are that bit cheaper, generally, though, and may be considered more 'trendy' by youngsters (and more manageable if they need to be taken to/from school).
Personally, must admit I prefer a larger screen, too, and full size USB keyboards plugged in (and recommend them for anyone concerned about spilt drinks, crumbs from biscuits, etc) so as to move the built-in keyboard from any 'danger zone'.
There have been a number of accidental spills reported in geeky_stuff and while sometimes it is only the keyboard (50 pound to 75 for replacement, plus labour costs) a liquid going in there can wipe out the whole machine, or severely damage other significant parts... battery 30 to 70 pounds, hard drives (lost everything including Windows if it happens).
Of course separate keyboard and mouse don't guarantee the machine is immune from cat pee, coffee or wine (adults!) but may mean the machine can be away from the edge of a table, or for a teenager, depending on how wide the lid opens, placed open nearer the back of a desk - safer from falling on the floor...
Or at some angle - remember those old wooden book holders for someone lying in bed, which could hold a laptop or netbook at 45 degrees, safe from a cat sitting on the keyboard [nice warm area!]
Full size keyboards have some appeal as they can be better used for touch typing practice, and the number pad being separate takes away the need for 3 or more functions on specific keys. (For me it is the fact nearly every laptop has cursor and other keys in different places, so backspace/delete get moved depending on manufacturer...
Try using 3 or 4 different makes / sizes of laptop/netbook and they get awkward to use at any speed. Plug in a 'standard' multimedia keyboard and I have volume controls, next/previous track, mute, up/down/left/right keys plus numbers in standard places, and the sleep key too.