Tire Recommendations:
Here are some photos of the 225-45/17s
I've gone through this with Saabs. It depends on what you want in a tire... good ride, $$, performance, etc. There is ALWAYS a trade-off. You can't get everything you want.
I want my tires to last a while, so I have some Yokohama YK520's. They are a bit stiffer on the ride department, but they are a harder compound. I would get Michelins if I was looking for the smooth ride (the other end of the spectrum). But they won't last as long. I'm using my Toyos now, becasue I want to wear them out and put winters on the wheels. The Toyos seem relatively "soft" compared to my Yokos.
I ran some Fuzion ZRs on my Saab wagon for a bit. They were great for the first 10K, but got too noisy later on. Keep in mind that the Saab 9-5 has had similar wear issues as the UK Mazda 5, but the Saab problem is with the rear, instead of the front.
What it boils down to is this... You need to decide what you want. Read the reviews, interpret them (I can usually tell which ones are moot - low miles so far, etc) and go with what you think will work. Most of all... REPORT YOUR FINDINGS to the rest of us.
DON'T FORGET: You can try different tire sizes, too. I have a set of 225 45/17s instead of the stock 205 50/17s
http://www.miata.net/garage/tirecalc.html