The only negative for me is that if I had a Mk5 GTI sitting in the drive, I'd rather sort it and take it on track than take the Mk3. In fact the same could be said really for any of the cars you have mentioned, with the exception being the Megane 225 as I really don't like them.
Out of all the cars listed the Megane has the best 'track' reputation, but it's the one you wouldn't take on track? 
that's vag blinkers for you
Not at all. I don't question that the Megane is the more capable car on track of the bunch but it's just not a car I like. The new Megane RS250 is really nice and I'd have probably recommended that had it been one of the options, but the older Megane 225 just doesn't do it for me.
If I could throw a wildcard in, what about a VXR of some description - either Astra or Corsa?
Plus, DH, the idea of taking the 'hot hatch' on track was something I suggested to the OP. If you look back, the OP was only looking for recommendations as to which car would be the best daily, and in that respect I definitely feel either of the VAG offerings would be best. The ST is good but perhaps a bit thirsty for a daily?
