I was between the Boss 302, GT500, (R)S4, 997 and M3. The Boss is a great track car but after being in an M3 it was very painfully clear that the Boss was still just a Ford -- no "luxury" options.
The GT500 on the other hand can be loaded to the hilt but as you may already know, it's possible to get the price into the 70's, on par with a loaded M3. I spent a long time trying to decide on paper because getting down to dealers is difficult with my schedule. Once I was able to do so I managed to easily rule out every car but the M. It just felt right. I'm like you, I prefer the V8 to a 6. I saw someone else mention the M6. The M3 sounds docile compared to that beast.
Assuming you haven't driven the GT500 yet, I would try to get into one. Since you like newest and latest you'll probably be very happy with a 662 hp car that gets better gas mileage than the E9x M's.