I personally found that spin speeds around 1000 RPM extract most of the water from most clothing. The only time I could see a benefit to using a higher spin speed would be with clothing which could retain water, like towels for example.
cfz is right, my thoughts behind high spin speeds causing premature bearing wear could be somewhat mistaken. I don't think it could help, but that's just IMHO.
Higher spin speeds have diminishing returns anyway. I believe that most anything above 1400 RPM is kind of pointless.
Someone else said it best on the forums though.. I'll paraphrase, "You have a dryer, that's what it's for, use it."
To put this into perspective, my old top loader spun the clothes at about 650 RPM. We found that did the job for most of the time, the clothes very very rarely came out dripping wet... and those were mostly towels.
My new washer spins at 1000 RPM and I find that there isn't much of a difference, unless I am washing towels. Then it's very noticeable.