Will ReadyBoost help at 8 GB RAM development machine

I have never found raid arrays really make that much of a positive performance boost for every day use. They certainly don't improve access times and that is what you tend to notice most in general use. I would also avoid raid-0 unless you don't care about the data being stored.

An SSD is the way to go to get a noticeable speed boost. Use a modest sized (60-128GB) one for a boot drive and a larger mechanical drive for bulk storage. If you want your games to load faster they should be kept on the SSD in which case you might want to get a larger drive (120GB+).

Almost any fairly recent SSD should be OK but Intel is best followed by drives based on Samsung or Indilinx controllers (Samsung are probably safer and Indilinx slightly faster). Cheaper drives based on JMicron controllers are OK only if you are on a very tight budget. If the price is cheap and there is no mention of the controller then assume it is JMicron based regardless of how impressive the specs might seem.

I don't know that I agree with the statement: "ReadyBoost focus is reducing RAM usage, instead of increasing hard drive access times."

It is primarily used for caching files, so they do not have to be read from the hard disk again, which is slower. Unless you have an SSD drive, I believe you would probably notice the difference. I saw a big difference, especially with things associated with the Interface.

http://en.wikipedia.org/wiki/ReadyBoost