Welcome to AO, dman
As Wrinx said, the best car really depends on what you are looking for and how much you have to spend.
A V6 would be very fast and sounds glorious. However, they are in a higher insurance group and drink petrol like there is no tomorrow.
The 2l TS sounds lovely and has reasonable running costs. Most people say that it handles better than the V6 too, as the engine is not as heavy (but I have never driven a V6
, so I can't comment on that).
The 1.6 & 1.8 TS will be slightly cheaper again to run, but not as much power (and I believe the engine is not as smooth as it does not have balancers).
The diesels will have the best economy, and good poke. I'm not a great fan of diesels, but there are plenty here who love them.
If you look at any cars with the Twin Spark engine, check if the cambelt has been changed in the last 36k miles or 3 years. With all the cars, make sure that the owner has been checking the oil regularly and also check for suspension noise.
Good luck with your hunt - and let us know what you end up with.