Welcome to THG, Prasad.
Regardless of which X6 you select the motherboard will make all the difference -- verify that BIOS options will allow you to disable Turbo (which will make tweaking much more exciting!) and adjust voltages.
There is not really any magic to the 1090TBE -- the unlocked cpu multiplier may seem to make tweaking easier but OC'ing with the system clock will take you higher with better stability (with the side benefit of increasing the IMC/NB speed from stock 2000MHz -- which leads to much greater performance overall).
There are also some great utilities: K10Stat and Phenom MSR Tweaker. They will help you manipulate up to 5 P-States with various voltage and clock settings dependent upon load --- an advanced form of AMD 'Cool & Quiet'
As Emperus noted the best is the one you can afford. The 1055T is a tremendous bargain and with good cooling and motherboard should have no problem running 14x240MHz (with a max turbo of 16.5x240MHz if you are so inclined).
And by the way --- it is *cache* not *catch*. Pronounced like Cash