Two Dogs,
At $1646 for all that I'd spend the extra on a graphics card. Why cripple a good system, especially when it's in the area you're specifically interested in?
Well, it probably wouldn't be crippled, but I'm thinking it would be less than optimal and if you can get a good deal on a graphics card as part of the package that's the way I think I'd go.
If the graphics card is going to cost as much now as it would in a few months then maybe try out the on board graphics first. If they're ok for you then you've saved a bit. If you need better then you've lost nothing if you buy a card later.
Good luck
AA