[CentOS] A question about RAID and partitions

I am about to begin the installation of a small server (no more than 20 
users), using CentOS with Samba to authenticate Windows XP workstations. A 
question arises about the organization of the filesystem. I hope that more 
experienced and knowledgeable users here will be able to give me some 
precious advice.

I have 2 120GB SATA disks on which to install the OS. I want to create the 
following partitions:

/boot
/
/tmp
/var
/home
/swap

Two options are now present to me:

- Create a single RAID 1 device with both entire disks and then partition on 
top
- Create several RAID devices, one for each partition (md0, md1, md2 and so 
forth)

Which one would be better from the points of view of performance, security 
and data recoverability?

Thank you!