My biggest complaint is that the semantics of CTRL-w and ALT-b are different. CTRL-w goes to the last space, and ALT-b goes to the nearest non-letter. Why did they define word in two different ways for the two different commands? I would kill for a non-deleting version of CTRL-w; if I have a long path in a command-line I want to be able to move to the previous parameter, not just the previous path element.
Ctrl+R SPACE seems like it's a bit iffy for some cases, especially since I use Ctrl+R so frequently for history searches. Using it instinctively (like I use Ctrl+W) wreaks all kinds of havoc; if I do something like Ctrl+R python to get a previously run command, then hit Ctrl+R SPACE, then it moves to the previous commandline that contains python instead of staying where I am and moving back a word. Still, something to explore -- I can probably find a way to use this.
