And concerning Stigmata, I've found that I get the best reactions from it when I perform it after several other tricks. When I just do it as a stand alone trick, I don't know, maybe people are not already convinced that I can do the impossible, so they're more curious about the method rather than truly amazed.
Same roputine, same presentation, but different reactions depending on the context. Weird, eh ?
It's nice to do a little set of a few different things for sure, but it really depends how you play your performances - When it comes to tables I'll often just throw it in as an encore outside my more commercial material, but if it's a more casual situation like the one mentioned when someone has already taken an interest, you can take the time to build an air of mystery around yourself and perform one thing that will truly blow their mind.
If they would like to see some more *cue business card* check out your site or give you a call.
Always leave them wanting more - I think in a paid gig you should always make the employer feel they've got their money's worth and everyone's seen lots of magic, but if it's a random situation it's your job to get people truly interested in you, so leave them in a state that makes them want to see more

That's just my way of attacking these kinds of things anyway!
D.