Thanks for all the advice.  The laptop information I have read has been very helpful.  My son has been mentioning the new "Ultra" books  Battery Life is appealing . So is lightweight and thin structure.  
Would any of these be intel Sandy bridge ? 
All have the solid state drives.     Would resolutions and screen quality be good for these  models?  They are all pricey!    
Here are some of the models he has mentioned.  
Toshiba Portege Z835 (1.4GHz Core i3-2367M, Intel HD Graphics 3000)
 
Lenovo IdeaPad U300s (1.8GHz Core i7-2677M, Intel HD Graphics 3000)
 
ASUS Zenbook UX31 (1.7GHz Core i5-2557M, Intel HD Graphics 3000)
 
Acer Aspire Ultrabook S3 (1.6GHz Core i5-2467M, Intel HD Graphics 3000)
 
13-inch, 2011 MacBook Air (1.7 GHz Core i5-2557M, Intel HD Graphics  
 Samsung Series 9 (1.7GHz Core i5-2537M, Intel HD Graphics 3000)
any comments would be appreciated
?thanks again
		
		
	 
All the notebooks you've mentioned run on Sandy Bridge CPUs; none of those laptops have displays that are upgradeable, but out of them the UX31 come with the highest resolution display at 1600x900 and the Air at 1440x900. For their screen size the standard 1366x768 is perfectly fine, but I would recommend against them as a main machine due to the cramped keypad (which some would argue you can get used to), small/limited display, minimal ports and lack of a optical drive (which may be up for debate as well)
If it was me I'd go with the 
Thinkpad 420:you can upgrade the display to 1600x900, add a dGPU and a core i7 CPU.  Thinkpads are built well, are known to last, and at 14" you have a good mix of portability and typing/display space - but obviously it is not an ultrabook.
Having said that, if your son/you are intent on an Ultrabook, I would go with either the Ideapad U300s, Asus UX31 or the Macbook Air in that order; The Ideapad has the best build of the Ultrabooks from what I gather, the UX31 has the high-res display, and while hardware-wise the Macbook Air has a great build quality I hesitate because of the price and the possibility that your son my have to have a Windows machine to run some of the programs for his curriculum (meaning you'd have to get Win7 on top of the laptop purchase).