wsmith5,
What you say about the Creative Labs Annihilator 2 MX is almost correct.  Yes, the DDR is double pumped on a 64 bit bus.  Yes, theoretically that would equal an SDR version on a 128 bit us, but only IF the clockspeeds are the same.  Most SDR MX's are clocked at 166 MHz.  The CL MX DDR is clocked at 143 MHz (due to 7 ns chips).
SDR: 166 MHz x 128 bit bus = 2.6 Gbytes/sec
DDR: 143 MHz x 2 (due to DDR) x 64 bit bus = 2.2 Gbytes/sec
We all know that the memory bandwidth is what holds the MX back.  That being said, you could pick it up (theoretically) at buy.com for $95 a couple a days ago.  It is still on backorder and has not shipped yet.  Yes, I did buy one at buy.com before I did the research.  I am thinking about canceling the order and picking up an SDR version, or maybe that Geforce 2 from compgeeks.com or ocie.com.  $100 for an MX ... $165 for a Geforce 2  ... decisions, decisions, decisions.....