Too true. Actually, I've never owned one, and I'm absolutely happy with the 15mm f/1.7, but I've (if briefly) thought about buying the 17mm f/2.8 as well as the 17mm f/1.8 - again. In a way, it's embarassing ...
M.
I would respectfully disagree with your last statement, which by the way totally amused me (because it was so true, probably!) - about it being, in a way, embarrassing, to consider buying lenses which are so close as to almost be overlapping. Because, though they are....they're also not. In my case, like you, I'm more than happy with my 15mm PanaLeica f/1.7, a lens I love so much that it has more or less acquired a permanent place on my Pen F. But the tiny Olympus 17mm pancake is different (at least, this is the rationale that I've come up with!) because a) it's sooo thin and tiny, and b) somehow it seems to 'mate' perfectly with the first several generations of digital Pens (the E-P1, the E-P2 and the E-P3). In fact, one of the copies I previously owned, I acquired because it had been attached to a beautiful 1st-gen E-P1, and seemed to almost be part of the camera. (So much so that Olympus actually made a standalone OVF for it, and occasionally sold the E-P1 + the 17mm pancake + the OVF as a kit.)
This wayward theory - that some lenses seemed originally to have been designed to go with certain camera bodies - is not original with me, by any means. I first heard it from several fine photographers (one of whom actually also owned a nice copy of the 17mm pancake which stayed permanently on his E-P1 as well).
So (this was all a long-winded wind-up to a confession, by the way), I couldn't resist the impulse - and have just bought my 3rd copy of the 17mm f/2.8 - which I suspect may become semi-permanently attached to my E-P3.
