I think the build quality on the 6th gen (96-00) Civics were a good deal better than the 7th gens (01-05) from what I've heard and read.
My cousin had a 2000 Civic from new and it lasted him for ages with virtually no maintenance (even when it needed it). Sadly, a ball joint went on it recently (while driving) with 230k miles on it and he sold it off to someone else who fixed it up and kept going.
I agree that its nice to know whats wrong with a car. I'm quite aware of what the Metro needs, and once those things are done it may well last quite some time. Its just getting it to that point that seems to be an issue.
I do absolutely love the mileage the car gets, its just silly easy to get too. Especially when I came from driving a 97 Sunfire with a horrid auto trans that I think I only ever got up to 35 mpg in the best summer tank. Then jumping in the Metro which handed me 60 mpg tanks in summer without a ton of hassle. Its tempting to keep it and continue modding it as I know there is more mpgs to be had. But, there are other options out there too, and I'll keep my eyes open I think.