You see more desktop AMD CPU's in laptops than you see thier own Mobile counterparts (just off the top of my head, I'd say this has more to do with price than how many companies have started to package AMD cpus).
AMD is almost always on the budget side, and although your looking at great speed and usually decent build quality (because Sony and others don't deal with them) - battery life, weight, and everything else is usually affected.
You have more choice with Intel parts, especially considering that every Taiwanese maker ships them out en masse in every style you could imagine. Go for the Pentium M if you do, its more expensive, but battery life and heat are major factors.
Of course.. If your looking for a light notebook and don't mind trying something new...
Yup.. Good ol' VIA, and Savage 3000 Graphics. Eh.. Its not like you'll be using it to play games anyway. Cheap, light, and decent for what you'll be using it for (only bad side is that I have never seen it in person nor a review of it, so there are quite a few unknowns going on).
Its best to consider battery life and performance in basic applications before anything else.
If you go for a gaming laptop, your looking at a year at most if you want to stay on the bleeding edge (and you'll soon realize that the battery life is horrible), but a light notebook won't seem archaic, and will still be usable on a performance level in four years (well.. Unless Microsoft makes Word anymore heavier.. Of course there is OpenOffice and AbiWord so.. Eh..).