I have a kindle (got it in August) and haven't really looked around at other e-readers, so I can't compare them, but I can tell you about my experience.
Like you, I read a LOT. I haven't had any problems with the battery life. After all, 2 months at half an hour of reading every day is still 30 hours of battery life, right? So even if you read 6 hours a day that's charging it every 5 days (which is probably less often than a phone, right?). I charge mine when I remember, which is probably every couple of weeks - and that's always when I think "oh, I should probably charge that a bit", I've never had it run out of charge (having said that, I don't use it every day). You can also charge over USB, so if you're keeping it with you a lot you could plug it into your computer whenever you're there? (you can still use it while it's connected to your computer by telling it to eject from the computer).
What I've found is that although I still read scads of stuff, I still read a lot in good old-fashioned book form. The main reason I still read loads of books even though I have the kindle is that I try not to spend much money on books. So most of the stuff I read comes from libraries - public libraries for fiction, and university libraries for stuff I need for my course (and although there is some ability to get e-books out of libraries I haven't tried that yet). (I am very lucky in that at home I live 5 mins' walk from a library, though, so having that as my main source of reading matter is easy - I'm sure my habits would be different if the nearest library was an hour away.)
However, I also travel on trains a lot and that's one main time when I like to read on the kindle, because it's so much easier to carry. Carrying on with the theme of not spending money, I've been downloading classic stuff that's out of copyright (Sherlock Holmes! G K Chesterton! Shakespeare! ... okay, I've downloaded the shakespeare but not actually read it yet). The other thing I really love the kindle for is reading pdfs. The faculty I'm studying at has decided to go eco this year and make all the readings we need to do available in pdf form online, rather than giving us a physical reader like they did last year. Given that they did that, having the kindle is brilliant because it means I can send the pdfs to there for free, and then grab it and go and do my reading on the train - no faffing about with the printer (and fewer wasted trees - I'd only print out readings now if they were something I was really interested in and wanted to look into further). I expect I will start paying for books for the kindle at some point but haven't done so yet. I was tempted to buy the first 4 Song of Ice and Fire (George R R Martin) books for kindle - there's a thing where you can get all 4 of them for a pretty good price - but was put off by lots of reviews saying that the kindle version is really buggy (bad and confusing misspellings being very frequent, apparently).
I've found the screen resolution really really good - I'm quite picky about brightness of screens and that kind of thing and the kindle is SO MUCH MORE COMFORTABLE to read on than my laptop screen (even with my laptop screen at minimum brightness). It doesn't look really white, it's kind of very light gray as a background colour which is much more soothing. The best thing, of course, is to try and find a friend who has one / somewhere that sells them to go in and have a look for yourself.
I must admit I don't read in the shower (although I do read in the bath) and wouldn't read in the shower or bath on an electronic device because I wouldn't want to drop it. I would instead stick an audiobook on loud (usually with a separate speaker, so I can turn it up properly loud to be heard over the water). The kindle has an experimental text reader which is okay but not great (obviously, it can't put emotion in or things like that, and it doesn't deal too well with question marks. But you can get the gist of what's going on).
I have the Kindle Keyboard 3G (so it has 3G and wifi; I got it just before they started bringing out the new ones - well, and most of the new ones aren't available in the UK now anyway). I like the 3G because it means that I can download new books on a whim; I mostly asked for that one because I knew that money wasn't a big problem and figured that this future-proofs my kindle as much as possible. The main thing I use the keyboard for is for the experimental browser (although since I just got a blackberry that surfs the internet I won't be using this any more) and for searching for books. If you're not planning to download books when you're away from your computer I expect you wouldn't really need the keyboard.
Okay, I've written a lot ... I will stop there. Any questions though, just ask