RAID 0 or Data Striping uses two identical disks to read and write data in parallel. In theroy it's supposed to double the read & write speed. It will give you about a 40% read/write speed increase. It will be a benefit if you need the extra speed. But also understand that if one drive fails in this array you will loose all the data.
You'll get 300G of striped HD space to mess around with.
Booting times, from my experience, is about half the time compared to using a single drive.
Now because your going to use one with the OS installed on it until you get the other one and your striping, RAID 0, you might loose all your data on the 1st disk when you create a Stripe array.
If you want to install an OS on a RAID format you have to save the RAID driver software on a Floppy disk. When you install the OS you will be asked if you want to install a 3rd party RAID driver. This is when you will select 'yes', insert your floppy, (excuse the un-intended pun), and install the RAID driver. Then the OS will install on your RAID 0 array.
It's easy if you know how.
Research it first because your wanting to install an OS on a RAID array and it takes a bit more effort.