In a laptop the 2gb on the video card is not going to make a difference from the 1gb version and the only differences between an i5 and an i7 is 100mhz cpu clock speed and huperthreading. Since you didn't specify the cpu I'm assuming a 2500k vs a 2600k and that would be 3.3 vs 3.4.
Can you link the laptops? The VRAM size doesn't tell us anything about their actual performance.
+1 As their are other things to consider. Generally laptops run on lower resolution screens, so you won't need as much VRAM. Without much info, I would say go with the i5 with 2gb's if it's cheaper. For most people an i5 is just as good as an i7, because an i7 only has hyper threading and a little more cache, and sometimes a little more core speed. But link us to the laptops if you want a more accurate answer.
I will check out the 'notebookcheck.net' link later. it looks good.
I cant post links to the laptops as I can't find them online. I'm in china, but the shop selling them is japanese. these things usually have similar models overseas, but they are invariably slightly different specs and almost always differently badged.
I tried googling them a bit, but gave up. that's why I kept my question to general information, but I can appreciate the specifics are important too! Those 'sandybridge core i' processors have so many speed variants, are there any particularly 'good' variants?
just in case anyone can find them, the model numbers are