Windows 7 64 bit Vs 32 bit - which is best?

• Which version of Windows 7, 64-bit or 32-bit?  32-bit processors are limited to 4 GB of memory, and typically can't use the full amount. The newer Intel 64-bit processors are theoretically capable of referencing 2^64 locations in memory, or 16 exabytes, however, all 64-bit versions of Microsoft operating systems currently impose a 16 TB limit on address space and allow no more than 128 GB of physical memory. 
• I have installed  the 64-bit version of Windows 7 in my recent Media Center HTPCs builds. I can't see a huge difference in performance, but I have noticed increased reliability and fewer crashes as compared to previous 32-bit builds. If you have at least 4GB of SDRAM, or are looking at the larger 8GB versions, then be aware that 64-bit Windows 7 is designed to make use of all that RAM efficiently. Make sure first that all your hardware (i.e., tuner or graphics cards) have the necessary 64-bit compatible drivers available.