If you are still on the fence about eReaders, I would very much recommend starting with the Kobo Mini. It was the cute form factor and pocket-able size that snagged me when I saw one in the store and I still love it! I can easily fit it in all of my purses, even the smallest one I use, and it is a perfect size to tuck into a seatback on an airplane (just don't forget it's there!).
I was also worried about the screen possibly being too small, but I have NO complaints about it for reading simple text-only (don't buy it if you want to read PDF's or graphical stuff). I took it on a plane trip the other month, and just got back from a family road trip last week and can say it performed admirably for both! I managed to read it in the car and also out by the pool in the full Las Vegas sun (something I can't say for my iPhone). For the current price ($40) you can't really go wrong! Then, when the next readers come out in the autumn, you can perhaps consider an upgrade for Christmas...
