It should be noted that if you want to make heavy use of LLE, especially LLE on thread, then a quad-core is worth the investment as you'll use up to 3 cores for that. I personally love being able to use LLE almost all the time.
OS: Win7 64bit Home Premium SP1
CPU: i5 2500k 4.4 GHz
GPU: ATI 6970HD x2 in crossfire
RAM: 8GB DDR3
CPU: i5 2500k 4.4 GHz
GPU: ATI 6970HD x2 in crossfire
RAM: 8GB DDR3