welcome shooter! great bragging rights on the 750ownership.
what is causing you the most trouble? you wanna know just about the only navigation tool i use? the "show unread posts since last visit" link. that, and the back button... if you use those in conjunction even after replying to messages you can always get back to the unread posts screen. if you keep reusing the unread posts link... it will reset. hence, using the back button.
when all else fails use the home button
when that doesn't work... go for a ride