As far as noise is concerned, I would look into some nice aftermarket fans for the case that are virtually silent. It shouldn't be too loud if you chose the right ones.

For a DVD/CD-RW, I would recommend getting one that would be compatible without the use of patchburn, but again thats your call. There were some 2x ones from about 2 years ago made by the same company that made the stock apple drives. They were rebranded with another off brand name, I can't think of it at the moment, but they were cheap and very good.

You should be find with standard IDE drives.

Best of luck and be sure to take plenty of pics for a mod guide.
"Fix it 'til it Breaks."

Jacob - EiC & Director of Technology
Mac Pro Quad 2.66 - 4GB RAM
160 GB SATA RAID 1 - 650 GB Storage
Quad 19" Widescreen LCDs
Accessorized to the Hilt