Just a note for everyone who is waiting for support for Totalmedia Theatre or PowerDVD, so that the MST Standby Tool does not set the system to standby, here is a fairly simple workaround to at least watch the movies without having to go into MST settings, so you can stay on the couch

:
(optional for extra simpleness):
Download Media Center Studio at
http://adventmediacenter.com/, install it and run it (exit Media center for this).
Go to the "Start Menu" tab.
At the bottom of the window there is an "Entry Points" line which you can open with the down arrow, do this.
Four all four items there that are from Arcsoft (you can see by the logo), or if you have PowerDVD, it's items there:
Double-click to open the item in a tab
In the field "When launched, do the following:", set the option to "Pause the currently playing media"
Save the item using the small disk item in the top toolbar, and close the tab
When all items are done, save the main menu using the save icon in the toolbar again, and close Media Center Studio.
Now, before you go and watch a Blu-ray or any other movie using TMT or PDVD:
Start any MediaCenter item, you can choose a music song, start a photo slideshow, go into Live TV or play a recorded TV, start a video, anything
(If you HAVEN'T done the steps above, pause the playback.)
Switch to the main menu (DON'T *STOP* what you're playing, it should still be in the 'Now Playing' line).
Start PowerDVD/TMT, either by it's menu icon, or by inserting a disc. (If you have done the above steps, the playback in the background will automatically pause, so sound and CPU use will stop for you.)
(background:) Since the playback of whatever you started will now be paused, MST will see Mediacenter as not idle, and it will not put your HTPC to standby.
When you're finished with your movie, don't forget to just stop whatever you started in mediacenter before the movie, so that the system will automatically standby again.
Hope it can help someone! (at least a little).