There are basically four different types of cards:
1. Reference cards .... nVidia's basic design, no extra oomph or features.....why bother (see 3)
2. Overclocked reference cards - nVidia's basic design with a better cooler and factory over clock (i.e EVGA SC series).... half assed approach IMO .... like putting a extra 200Hp engine in car w/o adding drive train that can handle the extra torque.
3. Factory overclocked cards with custom PCBs, beefier VRMs and better coolers (i.e Asus DCII, Gigabayte Windforce, MSI PE)). Same price as category 1 usually so why not take advantage of the extra ruggedness and performance
4. Same as 3 but a step further with multiple BIOS, voltage unlock and other serious overclocker features (i.e MSI Lightning, EVGA Classified)....worth the extra dough ? .... answer is user dependent.
I can see a case for categories 1, 2 and 4 .... I'd avoid category 2. I don't know what your needs are so hard to speculate further what might be best for you.