The way I understand it is WHS does not support a RAID configuration, mainly due to its disk extender/duplication method, but that is not to say people aren't using a RAID array on their WHS systems, as you will see browsing around the various WHS forums.
I haven't had any issues with the data corruption *hastily touches wood* as yet. The main tips that seem to be working for most people are:
Copy files to the server using Windows Explorer
Do not edit files directly on the server (copy them to a client and edit there before copying back to WHS)
Check that software on the WHS is not able to update files (eg WMP has an option to auto update media files with tags from the internet). Make sure this is turned off.
I'm pretty sure that Power Pack 1, which includes the data corruption fix, is currently being rolled out for beta testing with a view to official release in June.
I think you will be able to use the 64-bit Vista PC to access the shares, as it is just a network path (eg \\server\shares), but you would need a PC capable of running the connector software to create the user accounts and administer the WHS box.
http://www.wegotserved.co.uk/ is a good source of information for WHS. It may be worth you asking the 64-bit Vista question over there for a definitive answer.
All the best
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