Hey Wendell!!
I guess this is where i can kind of return the favour a bit..
the D5000 has it's uses, the tilt screen is a useful function that enables you to view circularly, the problem with this though is exactly that. The back screen, it doesn't feel as secure as it should.. for example the Sony ( i daresay) has a more secure back screen.. and with your current history with Nikon Repairs.. i doubt that this would be the best choice also considering the missing Screwdriver AF.
The D90 is where I would like to place my hand up for you to use. It has the sensor of the D300, it's dual scroll wheels are similar to that of your D3's, as well the lightweight of it does help. The screwdriver AF enables you to use you're old 80-200 as well. Creative Lighting System is in the D90 and i guess this is where I favor this option for you knowing what you do, + the price is VERY competitive on the D90 at the moment.
The AF has been updated to have 3D tracking. It is slower than the D300 but from what I've looked up, not by much. The sensor sensitivity has been improved on from the D300, and from what I've sourced out from DXOmark, better Lowlight performance, better color depth, and a slightly better Dynamic Range. Also there is a Kelvin
mode.
D300, many benefits in this, but then again.. why not just buy a D700

The benefit of the D300 over that of the D90 would be 9frame bracketing ( I doubt you'll ever use that though), the higher frame rate of 8fps, the better build quality and sturdyness. I guess all it would feel like is a D3 without the grip, and the layout is very similar to what you've got now.
My personal reccommendation lies in the D90. It's quality and it will get the job done. If you need a pricehunter, let me know via mob or PM.. I'll find the best way for you to get around pricing.
Cheers dude, can't wait till you get one =D
Marcus