Windows: IOmeter, iPeak, ATTO, HDtune - keep in mind that HDtune is not suitable for RAID arrays
Linux: bonnie, raidtest, rawio, iometer, blogbench, dd, iozone
Generally Linux is the superior benchmarking platform - most easy benchmarks for Windows only test sequential performance which is not that important for most users. Even though they might think otherwise.
Yeah there are 32MB and 256MB versions of ATTO; i recommend the 256MB one especially if you are testing RAID or complicated setups. But ATTO is not suitable for large write-back buffers (i.e. Areca) -- it will show fluctuating scores.