Many acronyms don't do such a great job at representing words as such. Here's some examples of things people say that are repetitive of something in the acronym.
ATM Machine (or as Carmen suggests, Automatic ATM Machine)
Individual IRA Account
(I saw this one on TV): RPMs Per Minute
*GCO Carpet Outlet* an extra good one!
PIN number (thanks, Mkunde)
VCM mechanism (experimental people)
PDF function (Anastasia in class)
Holy HBF (thanks, TBW)
SAT test (once again, TBW)
GUI interface (from http://beta.booklamp.org)
MLB baseball (TV Guide)
(I'll add more later...for some reason, it's hard to think of stuff like this when put on the spot).