Canon
5D is what I pine for. I have a 10D and haven't been able to convince myself that a 20D is worth the upgrade hassle. I'm sure I'd love either (even if my wallet wouldn't). I also have a Canon S30 which takes suprisingly good pictures (in all but low light - then the autofocus bites me).
In the non-stratospheric range, it all boils down to what combination of a)budget b)size c)picture quality and d)simplicity is right for you.
My mom got a Canon S60 (5MP), while my mother in law got a SD550 (sleek little thing). I'd buy the Canon S70 (older) if I were replacing my P&S. I tend to like more control, and RAW's the only way to get it.
-Zeke