I agree with Captain Antilles and add to that...

Darth Hade said:

Luke is surprised/shocked to see Vader, but we all know he shouldn' be since he saw exactly what he wanted to see. Making it look more in line with what I would would call a "dream-like" sequence would have been a better choice...

That's totally wrong. At no point is it said that Luke is in control of what he "takes with him" into the cave. I think you're missing the very point of what the cave test is for. It manifests the subconscious, it's not a Holodeck.