That article was a November 2000 review of a Presario 5900Z system that was brand new, a system that came out before August 2000. The price was $2300 - $2600. They don't cost that much now. A roughly comparable refurbished system from compaqfactoryoutlet.com is $600 - $650 now.
I went to Newegg.com and got almost $600USD in parts to upgrade his older system.
It looks like you got a reasonable combination of parts, and NewEgg has been a very good vendor in my experience (thanks Thane!).
It needs an ISA slot so his scanner will work. HP scanner with an ISA card adapter, some sort of SCSI I expect?
That's probably a reasonable assumption. If you really didn't want an ISA-slotted motherboard, you might have been able to use a PCI SCSI card. [link|http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x7f7dfd3f91d3d5118ff40090279cd0f9,00.html|This] page lists a link to [link|https://www.initio.com/store/index.htm|Initio SCSI cards] for various HP scanners. And there are, of course, very inexpensive USB scanners now too. FWIW.
It sounds like you were constrained by the fellow wanting a PIII. I think you found a reasonable solution based on the constraints.
I hope you're able to get the system together and debugged easily. Best of luck!
Cheers,
Scott.