[reprod]

My solution is to Pause the video and then touch the home button.
I do what I have to do and then I touch and hold on the Home button (to bring up the last 6 used apps)
Go back into Gallery...
Press play... I am right where I left off...

On a side note... are you using any Task Killers... if they are killing your tasks then there will no longer be any saved state for your videos in the Gallery application. Just something to think about.

There are a few great players in the works for Android... once these go public then we will have all the options we want. I am currently using demoPlayer and loving it. It is being developed by a guy on xda... It's looking to be the next CorePlayer...