In reply to your email re: a Donor Button, I indicated that I would prefer a link to our own Donor Page.
However, another option you did not provide would be amazing. Namely, a way that a donor could log in and make donations to multiple charities (sort of like a shopping cart) and then pay for them in one click. I'd suggest this as an additional option to whichever you pick for the "Donate to this organization" link. IMO, many people who support multiple organizations would find this very attractive.
While on the subject...I have long wanted to find a way that small non-profits like ours could offer to match employee donations to *any* non-profit. Perhaps there is a way Great Nonprofits/GuideStar can help with that. I'd be willing to incorporate the matching dollars into our benefits budget, but we'd need an administrator to help with determining when an employee makes a matching transaction and to keep us blind to the specifics since it's not our business who employees support...just that anything we matched is a legitimate 501(c)(3)).
Keep up the great work.