As said above it depends on the ride.
Nemesis - Has to be back/front right. the near miss on the front is awsome but i have a major passion for the back right seat too.
Rita - Got to be front seat, it's nott he best ride on park but that seat makes all the difference.
Thirteen - My least favourite ride of all but i prefer back seat to any other for that first drop.
Spinball -

Air - I like the back seat on this one as you get the drag feeling on the faster parts.
OBLIVION - I really don't find that any seat on this gives a different feeling, they are all the same intense ride.
"Life is a waste of time, and time is a waste of life. Get wasted all the time, and you'll have the time of your life!”