Pentium D > Pentium 4 < Pentium 4 with HT > Pentium 3 > Pentium 2 > Pentium MX
Pentium Extreme Edition > Pentium D
Pentium Core Duo < Pentium Core 2 Duo
Pentium Core 2 Duo < Pentium Core 2 Quad
Pentium Core 2 Dou < or = Pentium Core 2 Extreme X6800 [Dual Core]
Pentium Core 2 Quad < Pentium Core 2 Extreme QX6700 [Quad Core]
Pentium Core 2 Extreme X6800 < Pentium Core 2 Extreme QX6700
Intel Pentium Core Family > AMD
That's my opinion. Buy whichever you think it's reasonable.
Offtopic 
I can't add other characters 
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