Took installing Gimp. My preferance is just to use MS Paint for the rudimentary stuff, but Hi-Res needs a proper burial...er manipulation program.
(I am a fan of hi-res photos, but did not like leaving that pic up in such large res). Just FYI, I got the pic from you, Maniakmonkey, but only BBCode will work in these forums, not HTML.
I would not use an HTPC case on this computer as it's maximum processor speed prohibits any real benefit to that form-factor unless you need it to run especially quiet. These older Dells are limited to PGA370 and Slot "A" processors at between 233mhz (Pentium 2) and the maximum of the series, 1.1ghz (Pentium 3). The best graphics cards available for it were also limited to AGP 4x and Ram could not exceed 512mb (and never more than 256/stick, though most will only accept 128mb sticks and only non-ecc sync 133mhz SDRAM).
But I agree:
I would say if you wanted to put it in a new case there is no modding that should be needed unless you would like to modify what you already have. As far as materials, I would say that it depends more on your abilities and tools. Anything is possible but it is all up to you. I will restate the obvious this is an older computer so I am assuming you have a purpose for this computer, right? I think that you have two options and one has already been stated the other is putting the components into a HTPC case.
Best of luck, Maniacmonkey.