For the past couple years, I have worn the pants that I purchased at Mervyn's (department/retail). they are regular men's "dress" pants, (I always try to get the ones with the least amount of pleates). The reason being, I work at Target (Mervyn's cousin, Dayton's/Hudson's Corp) so I get the discount plus when they go on sale they are much cheaper than anywhere else... and those polyesther things don't do anything for my butt.
I have seen other, higher ranking officials wear the same style, and heard other guys insinuate that they are not appropriate. What is acceptable in your areas?