Western Digital Caviar Black 500GB 3.5" SATA 6.0Gb/s Internal Hard Drive -Bare Drive
Seagate SV35 Series 1TB 3.5" SATA 6.0Gb/s Internal Hard Drive
Western Digital Caviar Black 1TB 3.5" SATA 6.0Gb/s Internal Hard Drive -Bare Drive
what is difference between 64mb cache and 32 mb cache on th 1TB drives?
The best drive out of the three would definitely be the WD Caviar Black 1TB.
It is a very high performance drive at $100 which is awesome.
It has 64mb cache which is lots of space, and dual-processors to help it run faster.
Also it is the most rated (almost 1k.). The reason to why it has 4 eggs, could be the more bought the more DOA, but as far as I know the Caviar Blacks are really great.
And for your last question, I don't really know what cache holds. But 64mb cache is supposed to be faster than the 32mb when exceeding the 32mb limit.