When you're sharing a seed, document it from 0,0:
Press F3. Observe your X and Z co-ordinates on the left side of the screen. Walk until they are at 0,0. Take screenshots from there.
That way, we can actually go to 0,0 ourselves and see if we're really getting the same worlds. It's probably a good idea to take screenshots facing each cardinal direction (due north, east, south, west) and post them, since that would give you a better idea of how the world looks.
Also a note:
A Short Demystification of the Map Seed