hgm wrote:XBoard, of course.
I've had bad luck with xboard in the past - crashes a lot, difficult to configure engines (due to non-native UCI support and weird file encoding issues in the config file), UI drawing issues (board size too large for screen and trouble reiconfiguring it to fit), and I really hate the very old java style of windows and menus.
It also doesn't really keep a database of games played afaik. But that may just because I never got it to play enough engine matches before crashing to build up a database so I never looked.
But since I don't have a lot of options I'll give the latest version a try.
Just to be clear, I'm talking about xboard here. I've had a much better experience with winboard. Even running winboard under wine is better than running xboard native (in my experience). But winboard under wine caused serious lag issues the last time I tried to play in one of your online blitz tourneys and it caused my engine to loose it's games due to timeout. I think it was because it was redrawing the entire move list window between every move, and that redraw was just too slow under wine.