I know with my pump i lose about 5 pounds of pressure, so i typically put in about 5 PSI higher than what i want. I use a good floor pump that i bought at Mountain Equipment Co-op (i guess REI is kind of the equivalent in the US)
Actually my pump looks a lot like the Nashbar floor pump (www.nashbar.com)
It works pretty good, although i need help from my fiance to get it up to 125 PSI
what pressure are you pumping your tires to?
good luck!
Han