Reddit reviews Samsung NP300V5A-A07US 15.6-Inch Laptop

lenovo have got some pretty good work laptops with good intel i7 processors and for this particular model, 6 gb ram, which are both essential for video and music production.

Acer has a decent model one with a good i7 processor but only 4 Gb ram, which might not be enough for heavy workloads.

Samsung has another good model, which has similar specs to the lenovo (6 gb ram, i7 processor) but seems to be out of stock on amazon, but you could buy it in shops anyways.

Lenovo model

Acer model

Samsung model

There's probably a bit more out there that I might have missed, so shop around if you can ;)

edit: you should be able to play most N64 emulators on almost any laptop these days, but I'm not sure about running portal on integrated graphics cards which all of these have, you'll have to look for something more expenive for games.