I really fail to see the point of the E-P1, and I speak as a faithful Olympus customer since the launch of the E-1.
The problem is perhaps exactly that you, like most of us in this forum, are a satisfied SLR user, and the E-P1 is not primarily aimed at those of us who are comfortable with the bulk of SLR bodies and lenses, and are used to SLR features like wide lens variety, fast AF, and composing one-eyed through a VF rather than two-eyed on a rear screen. We should at least consider the possibility that Olympus and Panasonic are not lying when they talk of this sort of camera as being mainly aimed at people who are used to compact, non-SLR cameras, want the better performance of a larger sensor, but reject the bulk of a DSLRs and their lenses. And daring charges of heresy, I suggest that a great proportion of compact camera users have come to prefer two-eyed composing on the rear screen, and do not care in the slightest about bracing against their foreheads while peering one-eyed through a VF in pursuit of maximum stability. So the absence of a one-eyed VF may be a concern for you and me, but not for most target customers. Also, they are mostly not inclined to buy more than one or two lenses: even the great majority of SLR users do not go beyond two zooms these days. And for those who do want more lens choices, all Four Thirds SLR lenses are usable on the E-P1 via an adaptor, with slowish AF.
There may be a test of my "one-eyed vs two-eyed composition choice" ideas coming: if the rumored Panasonic GF-1 does indeed arrive with an EVF as an optional accessory rather than built-in, I predict that it will sell well, but a great majority of GF-1 customers will not bother to buy the EVF. Then again, Olympus is hinting in interviews of a second Micro Four Thirds model later this year with built-in EVF, and offering the EVF option through a separate model seems better to me than an protruding add-on EVF. I would go for such an EVF model so long as the body stays considerably slimmer and more "jacket-pocketable" than the G-1, GH-1 or any DSLR.
And the persistent talk of the E-P1 not being significantly smaller than a DSLR is almost bizarre: look at the side-by-side photos, or the weights. An E-P1 with standard zoom retracted is closer to an LX3 or G10 in size than to a DSLR with standard zoom attached. Perhaps this size complaint is because so many men have the idea that a camera is only "usefully small" if its fits in a pants pocket. Instead, for many what is more important is the comfort of less weight on the neck strap when carried for hours, or fitting in a jacket-pocket, or a back-back outside pocket, or in a large purse or handbag ... But forum conventional wisdom seems to almost ignore women as camera consumers! Olympus advertising for the E-P1 and recent small SLR models instead shows a strong targeting of women as potential customers.