Are all co-ops on a land lease?

1. No! Vast majority of NYC coops own the land they sit on.
2. read this thread and the many others here on land lease:
http://streeteasy.com/nyc/talk/discussion/18999-is-this-a-land-lease-building

I don't believe there is an easily accesible comprehensive list of land lease buildings. Hey brokers -- do the world a favor and make one please!

You find out by asking. These days most listings will disclose whether the building is land lease.

You also may find these past threads informative:
http://streeteasy.com/nyc/talk/discussion/2876-sale-at-101-west-23rd-streetwhat-is-the-deal-here
or
http://streeteasy.com/nyc/talk/discussion/6691-whats-the-story-with-301-east-63rd-street

With the exception of Battery Park City which is a completely unique situation, land leases tend to be toxic assets in the opinion of many people. As West says above, nearly all coops own their land. Land leases are exceptions.

What if the land lease is for 150 years?

Managing agent of Coop and its Offering Plan must disclose is Coop is
situated on a land lease

columbiacounty visited an apartment with a window in the shower and freaked out.

The best way to identify a land lease building is when you see listings with low asking prices but super high common charges.

Are socialists for land leases or against land leases?