eReaders: Suggestions?

I have probably been a tad bit critical of eReaders in the past, and with good reason, but I’ve been warming up to them somewhat as of late. The reason is that there are a lot of online magazines and magazines that release in PDF format that I would like to read more of, but I can’t because reading online for extended periods of time actually gives me a headache or bores the hell out of me.
But recently I’ve decided to accept some eBooks for review, only because the publisher is a itsy bitsy in size and while I would love to have hard copies I thought it would be beneficial to this small publisher if I just bit the bullet and read a few books in eBook format. I’m not, at this point, going to do this for every publisher, or every author, but special cases will be made because I can stand to read the occasional eBook, just not eBook after eBook.
Things are changing in the book market, though, and particularly in the short fiction market where online publishing seems the more “common” route than traditional publishing. I think this has pros and cons, but I think, all in all, this is possibly a better model for some publishers and probably something the big three are going to have to embrace to stay alive. Currently there are several online magazines that I read on and off, and I would like to read them more regularly, but there’s that “reading from the computer” thing and I’d rather spend my computer reading time editing my work or writing.
All this in mind, I thought I’d talk to all of you about eReaders and get your opinions on the matter. I’m thinking of trying an eReader–possibly asking for one for Christmas–so I can start reading online magazines more regularly and news stuff. If I find the eReading experience good enough to extent that to eBooks I might change my entire review model and take eBooks almost exclusively to save the publishers a bit of money.
The thing is, a lot of the eReaders I’m seeing have tremendous limitations for file format. So, what would you suggest? Is getting non-Kindle format books onto a Kindle too difficult to bother? What about Sony’s new eReader? Can I get PDFs onto eReaders or are there tools to help me convert to the correct format? What about plain text or txt files or .doc files?
What do you suggest or what are you experiences with eReaders?