If you really like your 172 but wish it was slightly newer/fresher, and with the added cudos of being a tweeked-to-near-perfection version of the clio2 platform, then go Trophy.
Choose a Megane if you simply want to go faster than any of the clio's with the added bonus of more practicality/civility when you're doing dailies. But Megane's have never really taken my fancy, I'm not sure if its the looks or what, but I think I'd love it when doing every day jobs but get bored quickly on a fast blast due to less revvy/racey engine (guess I should drive one to find out really!)
But I'd go for 197 R27 if it were me (or save up for a 200 cup). Purely because its a better all-round car, its chassis is genuinely an improvement in grip and response over the mk2 clios. Whether its any more fun than the others or not is surely a matter of individual opinion, but I'd have one if I could afford one.
Trophy is a great car, but so are all 1*2's IMO, but they're feeling old now. I also don't think the Trophy is quite as much of an icon or the future classic many hope it will be