The first model listed seems good to me, for what you will be using the system for. As for adding an optical drive, if your adding just a cdrom then you should also be fine. Will the cdrom be permanent? will it be used regularly? I ran a pentium III 650mhz, one dvd drive, and one 8x burner and 512 sdram with a 30 and 60 gb hard drive for like a year with no problems. oh and this was on a 120w psu, talking about pushing the limits, hehe