a few more points;
laptop, if it is used for long period of time has 2-4 drawbacks;
1) small or uncomfortable keyboard
2) small or uncomfortable mouse
3) small screen (although 2day u have laptop with 15 and 17 inch LCD monitors.
4) small and lousy speakrs
for first 2 problem, u can easiely and cheaply buy a normal keyboard and mouse and plug them in when ur at home. screen might b a bit more pricer. on the road ull probably use headphones, and u can always plug in a normal pair.
another drawback which u might encouter is lack of HD space. but u can always burn the data on discs and DVDs or buy an external HD.
if u manage to answer all the questions Avichay mentioned, ull b able to quite easily decide what 2 buy.