if you are a decently fast 800m guy, you should be up on your toes for part if not the entire race. Thus, you will want to get mid-distance spikes. The thing is, its all relative to how you run. Haile G. has been seen wearing sprint spikes for a 5k, for example. You could actually get away with a "sprint" spike such as the Nike Maxcat, or its Nike JSC predecessor, for up to the mile. A general list of shoes that would be good for a person running 800-Mile are:
Puma Complete Harambee;
Nike Zoom Kennedy;
Nike Zoom Miler;
Nike Zoom Ventulus;
Nike Zoom Maxcat;
Adidas Adistar MD;
Adidas Adistar LD;
Adidas Nova MD;
Adidas Nova LD;
Asics Cyber LD;
Asic Cyber MD.