Assessing harddrive tests

[DBissett]

Among other things, Tom's HW reports average read/write times and random access times on many harddrives. I've noticed that often when the avg. read/write times are very good the random access times are very slow, and vice-versa. I'm trying to pick a "fast" harddrive for a new build and am wondering what these different numbers mean and which ones are "best" for indicating how the drive would act in daily use. My computer use is "average" I guess, mostly office work and trading software. Which tests should I be focusing on? Thanks.