I have to admit the furtive street shot is tough to do - I tend to feel very self-conscious. My favorite for that kind of thing is still the Pen EE - its so discrete and retro I think people can't believe the thing in your hand is a real camera
I find friends parties to be a great way to practice portrait techniques although catching an unguarded moment is difficult with everyone so prepared to play-up or pose for the near ubiquitous camera-phone.
The least discrete cameras I have are the RB67 and Rolleiflex TLR - lovely cameras but they always attract attention (almost entirely positive).
The EP1 definitely falls into the EE territory particularly with the 17mm or 20mm pancake. I probably need to spend more time sitting outside a cafe and shooting more street scenes to get over "the fear".