Vista - Mobile profiles without server? Server AV? Windows 7 does RAID 5?

I have two questions and I don't see any groups that refer to Windows 7, or
that are relevant to my roaming profile question, so please excuse the
crossposting. I am watch all groups for any replies...

We have four users in our home and three computers. These computers run
Vista Premium 64bit, Windows 7 RC 64bit and Windows 2003 Server 32bit. All
are legit with proper licensing, etc. These computers are shared, so anyone
could be sitting at any computer. We may be adding a fourth PC as a media
server.

Now, my questions...

- I would love to have roaming profiles, but we don't run a domain
controller, etc. Are there alternatives to this? I simply want to sit a any
PC, log in, and have my documents, start menu, background, etc. follow me.
Is there a way to point Windows to a network drive for all my local profile
info?

- The 2003 Server is overkill for what we do. Just a file server, basically.
Trying to find a decent antivirus program, at a decent price, that will run
on a Server machine is difficult. What makes it worse is that I don't want
infected files moved, deleted or repaired. I just want them renamed, adding
the .vir extension. Because of this, I am considering moving this machine to
Windows 7. Does this sound reasonable?

- Since our Window 2003 machine if a file server, we have our drives in a
RAID5 array. If I move to Windows 7 will I have to lose the array or will
Windows 7 support RAID5 arrays? Will I need to rely on a hardware solution
or can Windows 7 create RAID 5 arrays line Windows 2003 can?


....so, simply put, what is the best solution to access the same desktop on
multiple machines and to server my RAID5 files to my household?