I am considering migrating to a MacPro, but will need to dual boot for windows only applications. Some specific questions:

1. Can I dual boot on two separate drives? Windows XP on one and Leopard on the other?
2. Can I run my Adobe CS3 Suite on both drives. (ie in XP and Leopard)
3. Will my render times speed up in Leopard since it is 64 bit and able to use more memory?
4. Can I partition two internal drives in Raid 0, separate from the other two drives? Or is it better to go with external Raid? (With my Boxx I have 6 internal drives, a system drive, a storage drive and a 4 drive internal Raid. My external 1TB WD Firewire 800 drive is way too slow compared to the internal raid.)

I am considering migrating to a MacPro, but will need to dual boot for windows only applications. Some specific questions:

1. Can I dual boot on two separate drives? Windows XP on one and Leopard on the other?
2. Can I run my Adobe CS3 Suite on both drives. (ie in XP and Leopard)
3. Will my render times speed up in Leopard since it is 64 bit and able to use more memory?
4. Can I partition two internal drives in Raid 0, separate from the other two drives? Or is it better to go with external Raid? (With my Boxx I have 6 internal drives, a system drive, a storage drive and a 4 drive internal Raid. My external 1TB WD Firewire 800 drive is way too slow compared to the internal raid.)

1 - Yes.
2 - As long as you have both Win and Mac versions, yes; when running either OS you're literally using the real thing, so windows will work exactly as it does on a PC - including viruses, spyware etc.
3 - Yes, encoding in Compressor is notably faster than Tiger was on the same machine. I can personally attest to this behavior.
4 - Never use an internal RAID, period, you'll never get the real benefit of speed or redudancy as you would from external arrays.

FW drives are slow compared to direct SATA connectivity, so if you want speed and safety then look at the plethora of eSATA, SCSI or Fiber external arrays. Do your homework and ask lots of questions, each setup has it's pro's and cons - and costs.