Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Olympus SP-610UZ and Nikon D80 side-by-side from the front, back and top in their relative dimensions. Olympus SP-610UZ has external dimensions of 107 x 73 x 73 mm (4.21 x 2.87 x 2.87″) and weighs 405 g (0.89 lb / 14.29 oz) (including batteries). Nikon D80 has external dimensions of 132 x 103 x 77 mm (5.2 x 4.06 x 3.03″) and weighs 668 g (1.47 lb / 23.56 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus SP-610UZ and the Nikon D80. Olympus SP-610UZ is clearly the smaller of the two cameras. Its body is 25mm narrower, 30mm shorter and 4mm thinner than Nikon D80. As you can tell, actually this is not a fair size comparison since Olympus SP-610UZ has a built-in lens but Nikon D80 doesn't. Once you put a lens on D80, its thickness will increase significantly.
Now lets look at the top view comparison of Olympus SP-610UZ and Nikon D80.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus SP-610UZ is significantly lighter (263g ) than the Nikon D80 which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on D80, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Olympus SP-610UZ nor Nikon D80 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing Top DSLR Cameras with Weather Sealing
LCD Screen Size and Features
Olympus SP-610UZ's 3.00" LCD screen is slightly larger than Nikon D80's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.