ChrisB, I wasn't commenting on your use of scotchbrite but was only pointing out that an extremely smooth wood surface can be reached with regular sandpaper. Going past a 600 grit with something even less abrasive is a perfectly reasonable thing to do, though probably 600 grit would be enough for most folks. At 600 grit I think we've hit the level where we are polishing as much as abrading. When I'm sanding things on the wood lathe, when I get to 600 I start to see the wood beginning to actually shine.
Regarding the use by some folks of steel wool, I rarely would use that on bare wood, though if a water based finish isn't used, the steel wool shouldn't cause any problems, particularly if a tack cloth is used to remove the remaining bits of the steel wool.