When I play an item from Videos, it always starts in full screen (hitting OK or Enter on the item, and then selecting Resume or Restart on the pop-up to play it). Might there be a setting for this?
Home goes to inset video, and then it's hard to get back to full screen. I just did a quick check on my test box, and I could only get back to full screen by left-clicking on the inset. Not helpful with a remote. I guess there might be another way, however. I don't use inset video, so not qualified to discuss beyond this point.
I'd go a step further with Ian's idea and disable the hidden menu when in inset video. I'm not sure how much one would change the view or delete a file with inset playing. Seems pretty logical to toggle between inset and full screen with Home. But, his intermediate solution would be OK as well.
HTPC: E7500, Nvidia 9500GT, ATI Theater 650Pro/Firewire Network Recorder/Avermedia Duet A188, NPVR 3.1.1, Win7 Pro
Test: Asrock 890GM Pro 3, Athlon X2 255 , internal HD4290, ATI Theater 650Pro, NPVR 3.1.1, Win7 Home Premium
Backup: Athlon 3200, Nvidia 7600GT, Network Recorder, NPVR 2.5.5, Win7 Home Premium