Guys:
The CSR from Staples I spoke with specifically said that STAPLES REBATE CODES will NEVER negate a MANUFACTURER-sponsored MIR.
So, in other words, if you've got an INSTANT REBATE code from Staples ($30 off $100, $30 off $150, $40 off $200, whatever) it will NEVER overrule or void the MANUFACTURER MIR. It may, however, negate any STAPLES-sponsored MIRs.
Just a headsup, I know this presents a problem for lots of n00bs out there.