I think that you're looking at a higher spec laptop than is really necessary. DS2's 2 year old Lenovo B575 runs Minecraft constantly without lag, even with all the extra mod packs and junk he's installed around it. It's a much lower spec than the one in your link - only a dual core E-350, far less RAM, etc...
DS1's old laptop is even slightly lower spec than DS2's because it was the same price but purchased a year earlier (for the equivalent of 230 GBP, but I think laptops are cheaper here in Canada?) It also plays Minecraft, but with very slight lag on occasion.
I'd not advise quite as cheapo a laptop as DS2's because it's obviously right on the edge of what's capable right now and so it doesn't leave much room for the future demands of any new releases, but somewhere midway between the two would probably be an ideal compromise.
I know it's a minefield (no pun intended). The guy in local computer shop advised me but I think it can't be that much to buy a basic laptop. He said the user would be frustrated on a machine which was too slow and the game would falter.
ooh I'd be interested in this too, as ds1 says my current laptop (a work one which I think is really good but have no idea what it is) is too slow for Minecraft - they've tried it and the game runs really slowly...??!
I have NO CLUE about this and want to get ds1 a laptop for homework at some point, but realise that it will also have to be good enough for Minecraft too...
However it's expensive just to play games on. Spec at least quad core/core i3:i5 processor. Not sure graphics matters that much as it is maths co-processor speed which is used to determine how fast game runs. I think this is level I would be looking at but hope there is some one more knowledgable who can advise.