I think it is great to have the choice. No stress, since it doesn't disappear once you have it. Think of it as the best libraries during the paper era, available at your finger tips. In the paper era, I didn't feel the need to read everything in the Library (even the small one), but I was glad to have choice.
One thing that helps narrow the choices, I won't buy DRM encumbered books. I have an enTourage and a Sony, and haven't used their book stores because of this. I have discovered new authors, that I enjoy very much, and don't have to bend my morals to enjoy their writing (I can strip DRM, but choose not to support those who allow it). Maybe this could help you. It would narrow your choice so you don't feel so stressed.