Few ?'s about x17's

With my desktop around 4.5 years old and me unwilling to screw with a BIOS update I feel it's time to look for a new computer.

I'd like to move to a laptop being as I don't game nearly as much as I used to and I'd like the ability to be more mobile.

The uses for this computer are going to be internet/netflix/gaming, and school.  So pretty much anything you could use it for.

So the two systems I've been looking at are the x17's at either lvl 3 or 4.  On the lvl 3 I'd add a SSD and on the lvl 4 I'd add a 500g HDD.

So my question is basically about the gtx 470m vs. the gtx 485m.  Is the 470 already dragging it's butt and if not how long should I expect it to run games before she's done?  Also is the gtx 485m worth the extra money.  I know its a matter of what I'll be doing with it but I also don't want to have to buy another laptop for another 4 years or so.  And no I don't care about Crysis.

So basically if I go with the 470m am I going to be mad in 2 years or should I pony up the cash for the 485 now?

Thanks for the help.