Hi Maximo,
a. Desktop machines are at least 1 year ahead with 'power'.
b. Laptops cost about twice the money if you want equal power as a desktop-PC.
c. The keyboard of laptops have less comfort.
d. The laptop displays are smaller.
e. The batteries always let you down when you need the laptop.... and have no AC-mains outlet.
f. Laptops have touch-pads or (tiny) tracker-balls. I prefer an ordinary optical mouse.
g. I have a Compaq laptop (notebook) for my job.... but NEVER, I repeat NEVER use it for private use.
h. In laptops it is impossible to change soundcards.
i. Only a few laptops have built-in CD-burners. (Expensive again)
In my home-studio I have an Athlon 1800XP and this one is OK for studio use.
I have no idea what laptops have built-in MIDI interfaces. (Perhaps the Apple ones ?)
My system was about 1700 USD including Plextor Burner, NEC 15" TFT and Midiman HQ soundcard
Roel