What type of work do you expect to do with the array? If it were only for a speed boost in a regular desktop system the 16K - 32K stripe should be more than enough but you will see an increase in CPU usage. If you like to work on uncompressed *.AVI files then use a 128K - 256K stripe.
Also, if you think about it...
smaller files (64kb) will be read about 64/30000 =... 2ms which is less then the latency time of 8.5ms
so the total time will be 2 + 8.5 = 10.5 ms
now if it is striped (when stripe size is small) then you have 64/50000 = ... 1+8.5 = 9.5
So for single read of small files it is not noticable.
For multiple reads bigger stripe is always better.
For bigger files bigger stripe is also better.
It seam smaller stripe is better for slower disks - 64/5000 = 13ms + 8.5 = 21.5 vs 64/10000 = 6.5ms + 8.5 = 15ms
So there is sweet spot depending on the disks speed.
All this is whenthe usage of the raid array is not well defined - like my pc (not a server, not a video edit only, not a lame desktop only...)