Good question, i like this one.
Always talk with respect however it all depends on the situation, say for example in the naffy (pub on a military base) no you wouldn't but you would always talk with respect and you definitely wouldn't ignore them.
You would only stand at attention when you are required to, example at a roll call, in a meeting with a higher officer.
Soldiers beneath myself, i would never expect to salute me as i walk by them, on or off base. i'd much rather them treat me as a brother/friend.
In my experience a new recruit will be more worried about meeting someone higher in the ranks because they wont know how to act straight away.
6 years in the Armed Forces and proud.