WMP11 has a mass tag editor. Highlight several files, right-click and select "Advance Tag Editor". You can also copy/paste album art in WMP11, which is especially useful if you use, say, Amazon.com's media library. In IE or firefox there will be a context right-click selection to "copy" or "copy image". After doing that there's another context right-click option to "paste album art" in WMP11. This is best done by viewing by album so that all the files in that particular album will update with the new art as a group.
The "find album info" function in WMP is somewhat hit or miss, IME, on actually updating the album art...everything else works fine though.
Remember that in WMP tracks in albums are grouped by "album artist", "artist" is a whole different field. This way you can have your "various artists" albums/tracks together while still crediting the individual artist, per song.
As far the files moving about, there's an option in the library settings that is probably ticked. Something like "arrange/organize music files based on rip settings." Untick that if you don't want your files being moved around.
However, consider that these programs (WMP, iTunes, Zune, and a plethora of others) are designed to manage file organization for you. The idea is that moving and manipulating files is outdated and should be transparent....your only concerns should be ripping, playing and syncing with your respective players. It took me awhile to get over my OCD with this too.