I'd have to say prolly .357 Magnum lately.
I don't own any .45s at the moment, but I'm sure I will. My current carry gun is a 9mm, but its not my favorite round. I carry it because I fell in love with the M&P platform, and I happened to find a compact one in 9mm before I find any others. Also, my wife has a 9mm so I was also steered in that direction for commonality in reloading purposes. I don't mind the 9mm, although I used to think I wouldn't like it because of over penetration issues. Now I'm of the mindset that with good HP rounds over penetration probably wouldn't be as much of an issue.
Except I don't yet have a CCW permit in Kalifornia, so I don't really carry right now.
Favorite rifle caliber? I really like the looks ballistically of a 300 blackout. I don't own one yet, but it just seems like a good round. Any thoughts?