Hello
What happens to all the games I purchase if Steam goes bust ???
You can already play them without an active internet connection (at least, you can for Counter Strike and Half Life.) If Steam did go bust and the DRM never got removed, though, I woudn't feel so bad about download a cracked copy.
Valve CEO Gabe Newell actually addressed that in an interview once, saying they would be able to deactivate the DRM so you could play steam games without being logged in (he also said they've tested the scenario internally). Sorry, but I don't currently have a link, but if i find it, i'll post it.
Some games you just need an internet connection, others don't. But there are no games that require steam itself, except maybe from Valve.