I've had good success with an open source tiling window manager for Windows called HashTWM [1]. I use it inside my Windows XP virtual machine to manage a bunch of hairy situations with multiple windows. I like that it actually does reposition new windows to fit inside the grid, and that I can easily adjust the middle "split" line so that my main window can become thinner or thicker.
Where it falls down is when you deal with modal dialogue windows, like the "Save File As..." window of Firefox, or the "Find and Replace" window of Excel. I haven't found a good way to overcome the issue of those modal windows being hidden, even with the "-i ConsoleWindowClass -i #32770" ignore options. It seems like Firefox, Excel, and Photoshop implement some non-standard ways of opening smaller windows. In these situations, I quit HashTWM, deal with the modal window, and then start HashTWM again (using quick keyboard shortcuts).
I wrote a program for use with AutoHotKey that helps create tiled layouts. I haven't used xmonad, so I don't know how it compares, but I've found it useful.
On the "move window / switch focus to workspace N" front, there's VirtuaWin (http://virtuawin.sourceforge.net/). You need to set up the Alt-1, Shift-Alt-1, etc. keybindings, but it works quite well.
Where it falls down is when you deal with modal dialogue windows, like the "Save File As..." window of Firefox, or the "Find and Replace" window of Excel. I haven't found a good way to overcome the issue of those modal windows being hidden, even with the "-i ConsoleWindowClass -i #32770" ignore options. It seems like Firefox, Excel, and Photoshop implement some non-standard ways of opening smaller windows. In these situations, I quit HashTWM, deal with the modal window, and then start HashTWM again (using quick keyboard shortcuts).
[1] https://github.com/ZaneA/HashTWM