The graphics card will probably suffice. It's more the applications you're using.
Photoshop will be usable, but not amazing. Video editing apps will struggle more, but it'll probably still cope. Check the minimum requirements of the stuff you use.
Another thought -- for a little more than the model you link to (or the same price if you or a close relative is a student at uni), you could get an Apple MacBook. Very similar good specs, plus Mac OS X which is more friendly with the stuff you're wanting to do.
iMove knocks the socks off Windows' movie editing apps.
http://www.apple.com/macbook
(I think the prices are �700 for normal model, or �600 if a student. Note that the prices may be a little more, but it's worth it for less hassle overall than with other laptops and operating systems (I'm looking at you, Vista).)