I lost interest when you said "Better than a Tivo".
If you've owned a Tivo and then tried to replace it with a PC running anything (Myth/Sage/Media Center/xbmc) you'll have found the same thing I did. After a year of screwing around - multiple hours a week - trying to make something that was better, I finally settled for something OK and spent so much time fixing it that at 3am one morning I ordered a Series 2 and a 320G hard disk and I haven't had to mess with it once.
I realized that I didn't want to play with a PC, I just wanted to watch TV.
If you've never owned a Tivo and used it for more than a month, you have NO IDEA what you're trying to replace.
Good luck! I'd love to find something better, but honestly, I haven't found it yet.