wrote:
All windows, doorways, and wall corners have crappy wooden trim
borders:

http://plaskon.netfirms.com/images/diy/corner.jpg (paste image link in
new browser)

When I take the trim off, there is a gap between the dry wall and the
sash.

http://plaskon.netfirms.com/images/diy/gap.jpg

What can I use to fill the gap?
And how can I ensure that the gaps between wall corners maintains a
sharp edge like this?

http://plaskon.netfirms.com/images/diy/seamless.jpg

I'd appreciate your suggestions.


I don't understand why you want to fill these gaps as this is normal.
It's the trim that covers this and you can replace the trim with a
different style but it must be wide enough to cover the gap. Perhaps
you didn't know that if you go into anyone house and pull of the trim
around the doors this is usually what you will see. Carpenters don't
try to make it look good since they know it will be covered up.

J