Can you help me choose an e-reader?

One of my christmas gifts is an e-reader and I am having a hard time choosing.

Price is an issue. I am deciding between the kindle ($140), literati/barnes&noble ($80 – on sale), and the libre/borders ($100). Is the kindle worth the added expense? I know the kindle holds more but the other 2 come pre-loaded with 100–150 books which is convenient, since I am lazy.

Does anyone have experience with this?