Video and image editing? Consider a MacBook Pro.
Video encoding? Core 2 Duo CPU (or better)
Get at least 1GB RAM (preferably 2GB)
P2P apps have no need for high-end hardware. They are, however, very useful for cramming your computer with all sorts of nasties (viruses, spyware, and other malware). Forget about them.
No Dell? Dell makes some very nice notebooks, IMO.
Nice design? Hard to beat a Mac.
2.5 Kg = 5.5 lbs. Therefore, you won't get anything bigger than about 15".
I am looking for a laptop in the price range of $2500-6000. It would be for High School yr11. But the plans i have for it need serious grunt power i would need it for Video encoding, Video editing (Premier Pro) and image editing (CS2) as well as for school work and p2p apps (all legal downloads ofcourse :D) the other applications i would be using would have a pretty decent load. so i need something powerfull, i would also like something mobile, anything over 2.5kb is a no no. also dell is no because they simply just suck! i am interested in good brands preferbly IBM (lenovo) or HP, Samsung, Fujitsu, ASUS and 100% NO Acer. btw if possible i need something that has a nice design on the outside and a list of models would be good