Microsoft Windows Vista help?

[(*_*)chica(*_*)]

I wanted to know what the difference between
Windows Vista Home Premium 64-bit with SP1
and
Windows Vista Home Premium with SP1?

Which is the better buy between these two laptops?>>>>
Im a college student and im NOT into gaming ex: WoW etc

HP - Pavilion Special Edition Laptop with Intel® Centrino® Processor Technology - Ceramic White >>> 8th one down the page
or
HP - Pavilion Special Edition Laptop with Intel® Centrino® Processor Technology>>>>> 4th one down

use the link below to view the page
your help is greatly appreciated

http://www.bestbuy.com/site/olspage.jsp?id=pcat17080&type=page&qp=crootcategor yid%23%23-1%23%23-1~~q70726f63657373696e6774696d653a3e313930302d3031 2d3031~~cabcat0500000%23%230%23%2311a~~cabcat05020 00%23%230%23%23o~~f510%7C%7C4850~~f534%7C%7C313526 71756f743b202d2031362671756f743b~~nf684%7C%7C53746 16e6461726420286d6f7265207468616e20352e35206c62732 e29&list=y&nrp=15&sc=abComputerSP&ks=960&usc=abcat 0500000&sp=%2Bbrand+skuid&list=y&iht=n&st=processi ngtime%3A%3E1900-01-01