welcome captainalf!
I had the same requirements as you do (and we are not alone
) and went for the Pocketbook 903. At that time, the Onyx M90 did not exist, the only additional possibility was the Asus DR900 (sith Sipix screen). I got it at a killer price, I had a deadline to buy, so I knowingly took a risk buying an untested deviec. I am still very pleased with it, although the firmware is not yet capable to serve the hardware well: by this I mean that I want to be able to take free hand notes, and at the moment this is only possible with anything but pdf files. But the annotation of other files now works likea charm - you can higlight, underline, make free hand notes with the stylus. They say the full annotation capabilities for pdf will also come, and I believe them (though you will also find a lot of disgruntled people, who by the way do have a point with the PB302). The competition from teh other devices can only be good in this respect. For the moment, what you can do is select a piece of text, save it as an image, and then annotate that free-hand. Better than nothing (i.e. I can work with that), but this device can do better.
The browser is there already, including a nice hacked version that works better than the original one, but it can be perfected (e.g. there is no landscape mode). So, no problems for basic brosing. However there is a promise of a reviesed browser, and again I believe them as this is already implemented in their "newsreading" application. Forgot to say, you can browse whichever site you like (including listening to online radios - there is a hack for that).
However, if any of these are killer features for you, I would recommend you do
not buy anything on a promise. And for this reason, unless you are in a hurry, I would wait to see for the M90 to come out and for the first reviews. I am sure also comparisons between the M90/1 and PB902/3 will come out, so that can only be good for you. For instance, the Onyx has a Pearl screen, the Pocketbook does not, but I can tell you I have read in any light with no problem whatsoever. The lovely thing about the Pocketbook is that you can customise it in many many ways, so it is very flexible. This may also be true of the Onyx, but I do not know.
I am in a similar position to you in the sense that I am going to get another of these for my household - I expect I will end up with another 903, but who knows, I am keeping an open mind. I would also suggest you lurk the Pocketbook and Onyx forums to see what's up.
Dictionary use is fine, I presume this is equivalent across readers with dictionary capabilities.
Battery life not a problem (though any audio use suck a lot of power - brwsing also does, but not that much), in the sense that you forget the last time you charge it - but this I think is for most e-ink.
I am not sure I understood what you meant regarding references.
As you see, I am "ignoring" the Kindle - I have a point of principle against them, in the sense that
I want to be the control freak, not Amazon checking on me, and I very much resent their use of their unique format - but that is me, again you should see for yourself. In this sense, Pocketbook is perfect - but as I said, I have already voted with my feet, so I am biased
There are other devices you might want to check out, namely the aforementioned Asus DR950 and the Entourage Edge, which is an e-reader plus tablet with some nice features, like immediately copying a webpage from the tablet browser to the E-ink side (problems for me: too heavy at 1.5 kg, plus the company migth not be around for much longer)