I have had the same problems, and I gave up switching back and forth between surround and extended mode. To keep the windows on the correct monitor and prevent maximizing across all three screens, I have been using DeskSoft's WindowManager. Works for explorer windows and most programs.
http://www.desksoft.com/WindowManager.htmFor example, I have a desktop shortcut labeled "Desktop Right" and it is trained to open on the right monitor. Same for a "Desktop Left".
Most other programs (Firefox e.g.) are trained to open on center monitor. Though some (like iTunes) are trained to open on the left or right.
Works quite well (I have been through so many programs!) and I just upgraded to 3 Asus 27" screens and had to retrain all my programs for the new resolution, but after 20 minutes, back in business.
For the Start Bar, I use a QuickLaunch Menu to fill the entire left side with shortcuts to Games, and this leaves the open applications on the center screen. I use a second QuickLaunch Menu on the right side for applications.
Been working like this for years now, have not used extended mode during that time.