As the previous posters mentioned:
- get the slowest processor offered (around a 1.6 GHz is standard these days and is more than sufficient)
- get at least 1GB of Memory (note, not hard-disk, not sure how technical you are so forgive me if you already knew the difference)
- for maximum mobility, invest in a high capacity battery (any pitfalls ergarding these that anyone is aware of?)
- pay attention to screen size, it is usually inversely proportional to mobility, unless you don't mind logging around a 6-lb laptop (I think 14 inch is a good mid-point)
- opt for Windows XP professional, over Vista.
- For law school, you probably only need Window's student's edition (cheaper then professional)
Aside: invest in a small laser printer (pretty good ones can be found for under $200 these days). Will turn out much cheaper than the inkjets.
Will update if I remember anything else.