Well, I've been collecting for a few years now, and have tried to stick to variations on the absolute classics in the horological world. I like limited or numbered editions, which usually have more classic design cues that are a throwback to the originals, though if possible, I try to seek out some of the originals themselves.
I'd like to compile a list of the absolute classics for each brand, because I've read various lists that outline them, and only a few are ever really common among all the lists. I'll start it off:
Audemars Piguet - Royal Oak Jumbo 5402 (now 15202)
Omega - Speedmaster
Rolex - DateJust, Submariner
Jaeger LeCoultre - Reverso
Heuer - Monaco
Breitling - Navitimer
Lets get this list going!