Back to OP relevancy, small 2 seater convertibles I like:
MX5 without a doubt
S2000, I want to like it but no torque and the bonnet is too long plus the interior not special enough. And weird size wheels. Lovely gearbox and I know the engine revs and revs but I don't think it sounds too good either and making the engine go on and on while also not sounding good doesn't do much for me.
Z4, long bonnet but far better interior materials than s2000 and more driveable too.
Booster, the latest two models are nice, the previous ones are a tad frisby looking.
SLK: the new ones feel better on the road than the old ones, but really, look elsewhere if your primary goal is fun.
Fiat 124: glad it exists but I'm more into MX5.
I'd either get a newish booster followed by MX5 followed by Z4.