I have an S3 Sport 220. Had an S3 1.6 Touring before that. They are both special and an event to drive. Every time. Always get lots of positive attention. The 1.6 has 80% of the magic but can be easily embarrassed in a straight line (though the purists know that's not what it's about!). The S3 220 is fast, and has lots of nicer features. I bought mine as a custom factory build, went to see it being built, and I've barely lost money so far. It'll probably appreciate above what I paid soon. As for S1, S2 and early S3s, the only way is up now I think. Servicing is cheap and fixed price at the dealers. Insurance is not bad for me (relatively speaking - all insurance is a rip right now). Mathematically, when looking for a sports car/hot hatch, it was all-in the cheapest over the 3 years I worked out due to low depreciation, cheap servicing etc.
Before kids I had one as a main car. Not the most practical and the boot will warm up your shopping but I loved it. Now I have one as a second car due to family requirements. Can't see me ever selling it. On the right b-roads on a nice day in the UK, I don't know what is better than the Elise. The handling, sense of speed, fun etc. More power can't be easily exploited and the only more engaging options are less practical and more 'raw' - e.g. Caterham, maybe a bike! I also have a Focus ST and it's not as 'fun' until pretty illegal speeds.
If you don't think it works for you on paper then don't test drive one as you'll probably want to buy it regardless..