Hey Tony,
First off, my advice is to not let your GAS dictate. It sounds like you want a lens that's faster (and perhaps smaller) than the kit lens. All of the lenses are capable performers, but they each have different strengths.
My default recommendation when it comes to the first lens purchase beyond the kit lens is the P20. It's really a fantastic, fast, sharp, small tool. However, from what I've read, between it's (relatively) slow AF and the banding issue at high ISO, it's perhaps not the best fit with the OM-D.
The O45 is also a nice piece of glass, but you may find that the 45mm focal length is on the longs side for a general-purpose walkabout lens. You may find it tough to frame your shots with this angle of view, particularly when you're shooting indoors (where you'll find yourself backing into walls in an attempt to get a wider view).
That leaves the PL25 and the O17. Obviously the 25 is much faster and much more expensive which makes it tough to compare these two.
I think I would recommend a lens you omitted from your list: the
Panasonic 14mm f/2.5. You can pick one up on eBay (generally stripped from a kit) for less than US$175 (including shipping), which qualifies it as the
best deal in Micro Four Thirds.
Particularly since you mentioned that you're already pressing up against the limits of your household comptroller and that you want to (eventually) pick up a pancake, this seems like a good, inexpensive way to expand your kit.
One exercise that you might do to help decide which angle of view is most useful for your purposes is to just tape down the zoom on your kit lens at each of these focal lengths and see which best fits your needs.
1Thanks
Help me feed the GAS: O45, PL25, O17, P20
