Cache or SATA III 6GB/S Connections, What is more Important?

Hello, i am creating new PC i am confuse with hard drive selection i have two option to chose from please help me which is better ?

(1) from WD with SATA III with 16 mb cache
(2) from wd with SATA II with 32mb cache

below is my configuration
Intel core i5 2320
Intel DZ68DB mother board
16gb corsair DDR3 1333
ASUS DVD writer

Cache is more important than SATA connection with regards to HDDs.

HDDs can be SATA III “compatible”, not SATA III “capable”.
A single HDD cannot spin fast enough to saturate a SATA II port, let alone a SATA III port.