I'm glad to see, by reading some of the 45mm Oly lens threads, a lot of people are keeping their fine cameras. I see a lot still using GF1, EP1, G1, EPL1 and so forth. In looking at posted photos I see no difference in IQ in these and the new cams, especially with a nice lens like the Oly 45 1.8 or the Panny 20mm 1.7. It seems a lot of people aren't going for the slow addition of features, not affecting IQ hardly at all.
I agree. I have been shooting with a DSLR since 2004 and with m4/3 since January, 2010. I have always put lens purchases above upgrading to the latest body. Not only do I still shoot with the GF1 I bought in January, 2010; I still shoot with the Nikon D200 I bought in 2006!
Whenever I have been tempted to purchase a newer body I've come to the conclusion that it would be kind of a boring upgrade that would only improve a small percentage of my photos by a small amount. But adding more lenses would truly expand the types of photos I am able to capture by giving me things like a wider field of view, a tighter field of view, a wider aperture, fisheye, macro, better optical quality, etc.
Even when I went from a 6MP Nikon D70 to a 10.2 MP D200 that had more resolution and less noise at high ISO by at least a stop, I always said I would take the old D70 with a quality lens over the D200 with a mediocre lens.
When someone says they are thinking about upgrading cameras just to get a newer sensor I ask them: Are you already using the best lenses you can get for your type of shooting? Are you using the best technique, including a tripod when necessary? If so, then are you really pushing your sensor to its limit that much? If the answer is yes then the newer sensor might give you enough of an improvement in enough of your photos to be worthwhile. If not, then you might be excited about the purchase initially, but later wonder why the photos you're taking look just like the ones you captured with the previous model.
Of course it's nice to upgrade cameras every now and then, and if you can afford it and you're happy then why not? But me...I'm quite happy with the GF1. For me its significant weak points are: The merely adequate LVF1 and the poor implementation of Auto ISO (this might be true for newer models as well), but the latter is only a real issue when I'm giving the camera to someone else to take photos of me with. If Panasonic announces a newer external viewfinder that is higher resolution and still compatible with the GF1, I might just upgrade my viewfinder.