The N80's sliding part gets a bit worse as you use it, sometimes I wonder if mine is going to slide horizontally soon , the Camera seems fine to me, though lack of auto-focus stinks at time (you have to hold camera still for 2-3 seconds), battery life is not so good, so you need chargers to be around + extra batteries.
I'd say if wifi is not important go with N73 or just wait for the N95 if you can afford it.
I mainly got mine for wifi, but I ended up keeping my data plan, which now I wonder if I shoulda got the N73 instead, though I have to say wifi is nice for browsing, downloading/uploading stuff & Fring/VoiP type applications.
-H