I have been going about the E-P1 since I got it and thought it best I write a mini-review of it. (I will be doing the same with my newer E-P3 at some point.
Firstly I should say that I am a mere amateur. In fact I wouldn't even say that. I am someone who has a basic knowledge of the basics of photography and like to dabble. So for all those pedantic pixel peepers, this is not a review for you.
The E-P1 in my opinion is a modern design classic, so much so that Olympus haven't drastically changed the look of the two cameras that replaced it - E-P2 or E-P3. I suspect they didn't have too as the first design was so good. It is a very handsome camera and I particularly like the raw aluminium finish and the reassuring weight. It feels just right in the hand and coupled with the pancake 17mm lens makes a surprisingly portable package. It screams premium product and is gorgeous to look at.
Build and handling
Housed in an aluminium case it feels solid and very well built. My E-P1 is getting on bit but all the dials and buttons are still tight. I get the impression that if I continued to use it regularly for a couple of years, things would stay they same. The camera is very easy to hold for extended periods of time and the different functions can be changed swiftly. The mode dial is internal and I prefer it to the dial located on top of the E-P3. The menus are very comprehensive and once you have the hang of them easy and quick to navigate.
With just over 12 megapixels the files the camera produces are very good. Low light performance isn't as good as its more modern counterpart but if you're a day shooter as apprised to low light, you should be fine. With the 17mm lens you can produce fairly sharp results and a pleasing about of bokeh. There are a number of art filters you can use but some do tend to slow the camera down. I have been very pleased with the results I have obtained so far and certain that I will become even happier once I fully get to grips with it. I mainly shoot buildings or the odd bit of street photography and it seems great for both. The jpegs straight out of the camera are great and even though it can shoot in RAW I have tended not to need to use it as I have been so pleased with the jpegs. Autofocus is not as fast as the modern competition and not anywhere near as fast as the lightning speed of the E-P3 (which is incredibly fast)!!
Any camera that makes you want to take it with you wherever you go and is a pleasure to use can only be a favourable sign. For me the E- P1 is a great little camera. I used to have a hulking Canon DSLR but rarely took it anywhere as for me it was a hassle to carry around and wasn't very discrete. The Pen line of camera are not exactly something you could put in your trouser pocket (you could but people would be constantly asking mid you were please to see them) but I do tend to take it everywhere.
If you can get well looked after example you won't be disappointed. A good one on eBay with the kit lens might set you back £150 -£180. With the gorgeous 17mm it might be the top end of this price range or a little bit more. Well worth it and I haven't regretted getting one (although I was given it) and love it.