I had a pair of piranhas. They ended up having too much room in the toebox for me - I only raced in them like once. They were a 3.9 oz shoe - lighter than most spikes on the market at the time.
My favorite for training and racing half marathon and above was the Adizero Rocket. They felt faster than the 7.4 oz would suggest and they lasted over 2000 miles.
My favorite for shorter races was the nike streak xc/lt series. I'm still training in deadstock of the streak lt 4. I had and liked them all xc 1-3 and lt 1-4.
I also liked the brooks t3-t5. They had kind of a weird shape, but were just about perfect for my feet.
For spikes,
I liked the ike forever xc for anything that wasn't a grass track course.
Reebok distance fosters for grass track xc and track.
For casual shoes
Puma Taper sp. I ruined the one pair of them I had by running in them one summer.