I'm not afraid of dying, as long as it's not some horrific death, but I'd be sad that I'd be saying goodbye to the people I care about.
If I knew for a fact that I had a day left on earth, I'd make sure I let my friends and family know what they mean to me. If there were any apologies to be made, I'd make them. But then for the rest of the day I wouldn't want to spend it with my friends. I know this sounds really lame, but I'd want to spend it with my mother, because she is the most important person in my life and never treated me like I was some dumb, irresponsible kid, and we also have a lot in common. I'm not saying I spend all my time with her (at the moment she lives in a different state, anyway) and I don't consider her a best friend or anything, but she's a great parent. So I'd want to be with her for my last few hours. Talk with her, maybe watch a movie with her, etc.
Also throw in some praying, eating my favorite foods, and visiting After-Darkness and Buffy Boards one last time.
And then I'd be ready to go. 🙂
However, about what I said earlier...I already try to keep from letting things get in between me and other people, and I try to apologize when something is my fault, but I'm sure on my last day there'd be something to make up for.