As far as I know EIDE drives are compatable with IDE motherboards. I have never had a problem with hooking up a new HD to a old MB. I have even hooked up a brand new 80 Gig HD to an OLD 486 MB.
As for the RAM, with todays prices you should really load up on it, especially since the MB only has 2 slots. With a max of 512MB I would get at least half of that.
Cheap DC-DC PSU? LOL! I don't think there is such a thing.
Good luck on your endevor!