If it was me, which it isn't, it would probably be:

1st choice: 96-99 M3....Look good, handle great, good power, strongly built, track and autocross monsters, and top speed stability. Also comfy and luxurious (4 door anyone ). But higher upkeep bills.

Close 2nd: S2000....Handle/go/stop very well, Honda quality reliability, decent maintenance charges. But not much room and probably wouldnt be as good a daily driver as the M3.

IS300 wouldnt compare, and you'd always be waiting to dump 5k into a GTE swap. Same goes for the Supra. Awesome car but a money pit. SRT-4 is just an econobox with balls. 911 would be nice, but expect maintenance bills to be higher than the other choices.

My philosophy is, get something you love in stock form, and you could drive for the rest of your life stock, and add on whatever you can to make it even better. I've learned that getting a car you plan to mod heavily from the start will never leave you satisfied.

Good luck.