Ladder vs NL vs SP vs Open

[Scudstorm]

What are the differences? Apart from the obvious (ladder-only drops, rws, recipes, dclone, uber trist), are there anything else?

I always assumed there wasn't, until I stumbled upon a statement by SSoG which said ladder monsters have more hp (!). Was that only a "previous patch thing"?

[NASE]

Ladder monsters have more hit points. It should be all in the summit. http://classic.battle.net/diablo2exp/monsters/

safe for the obvious ladder only items and realm only events, there are huge difference in community. The single player community here is clean, yet I'm sure there are other single player communities filled with dupes and hacks. And this is definitely sure for open bnet.
Same goes for ladder versus non-ladder in smaller extend. Non-ladder is filled with dupes, perms, hacked items from previous versions where the ladder 'only' has those from the currect ladder.
Offcourse, you can chose not to utilise these items.
And there is one difference, they reset the ladder once in a while. So if you are more casual, you might not even end up with the top end items, something you could achieve on non-ladder over the years.

[vknez]

pvp is stronger on non ladder, just cause of acumulation of items through the years...