the most demanding usage you listed is the video editing. Need pretty good CPU / GPU combo to make it work smoothly / quickly.
Asus
A45VS-VX028H, i7-3630QM + Nvidia GT640M@RM2999[2.4kg], 4GB, 750GB, W8
A45VS-VX026H, i5-3210M + Nvidia GT645M@RM2199[2.4kg], 2GB, 500GB, W8
K46CB-WX060H, i5-3337U + Nvidia GT740M@RM2199[2kg], 2GB, 750GB, W8, 4-cell, OD
A55VJ-SX093H, i5-3210M + Nvidia GT635M@RM2499[2.52kg], 4GB, 750GB, W8; color: black
N56VB-S3070H, i5-3230M + Nvidia GT740M@RM2899[/b][2.7kg][B&O], 4GB, 750GB, W8
Sony
Vaio SVF14218SGW, i5-3337U + Nvidia GT740M@RM2399[2.4kg], 4GB, 500GB, W8SL; colors: white/black
Vaio SVE14137CV, i5-3230M + AMD HD7650M@RM2399[2.4kg], 4GB, 750GB, W8; colors: pink/white/black, Vaio backpack
Vaio SVE15138CV, i7-3632QM + AMD HD7650M@RM3099[2.7kg], 4GB, 1TB, W8; color: silver; Vaio backpack
Vaio SVE15137CV, i5-3230M + AMD HD7650M@RM2599[2.7kg], 4GB, 750GB, W8; color: silver; Vaio backpack
Toshiba
Satellite L40-AS109Xb/G/W, i5-3337U + Nvidia GT740M@RM2199[Onkyo], 4GB, 750GB, 3 years local warranty; colors: Blue/gold/white
Satellite M840-1034XG/XP/XQ, i7-3620QM + AMD HD7670M@RM2699, 4GB, 750GB, W8SL; 3 years local warranty; colors:gold/pink/blue
Satellite P840-1004X, i5-3317U + Nvidia GT630M@RM2999[harman/kardon], 4GB, 750GB, OD, W8; backlit keyboard; 3 years local warranty
Satellite L50-A100X/XW, i5-3230M + Nvidia GT740M@RM2199[Onkyo], 4GB, 750GB, W8SL; 3 years local warranty; colors:silver/white
Prices are RSP, negotiable.