Old P4 2.4 to build into FreeNAS or upgrade current system?

Hi Everybody...

I recently built myself a decent gaming rig about 6 mos. ago. Now I have this old Dinosaur Pentium 4 2.4gz lying around and I can't bring myself to just throw it away and I don't think it's worth anything really to anyone else.

I want to rip my two hundred some cd's onto a pc, but don't want to fill my 750 gig hard drive on my new build. I was thinking of turning the dinosaur into a FreeNAS system and modding the case with some cool stuff.

The old build only has a PATA 35 gig hard drive in it, so I think all I would need is a hard drive controller card and some hard drives right?

Or Should I just invest in an external HD or something like that on my new rig?

Old pc has a p4 2.4 proc, Biostar mobo that doesn't even have a pci express slot its so old, 1 gig ddr133 ram, don't know the p/s, 35 gig western digital hd. The motherboard could potentially have some issues so I could be talked into finding a new(er) mobo to make this easier.

Thanks for any thoughts, or suggestions. I am thinking I wouldn't want to spend any more than $100 to $125 on some drives and controller card.

Please let me know if I left out any info.

-Thx