What Sustained Disk Transfer Rates Do You Get?

Mr. Jackson asks: "What kind of disk transfer rates (MB/s) do people get in the real world when moving around large (100s MB) files? Either every machine in our building is mis-configured, or our notions about what we were getting are way off. I've tested half a dozen machines, mostly Win2k, some Linux, by just copying a large file and timing it with a watch. 8 MB/s seems to be about average for inter-disk copies. RAID 1 (stripped) got as high as 12 MB/s after fiddling with cache settings. RAID 5 was as low as 2 MB/s. We all thought the numbers should have been around 30 MB/s."