Canon D7 EOS vs Nikon D300?

Which is the better camera
Its going to be used for wedding and portrait photography

If you have to ask that question, then i think you're far from ready for doing weddings, the most success-critical field in photography. It may get you sued if you screw up there. And it's the 7D, not D7.
Both are very capable cameras. Going by the pure specs i'd give the edge for these purposes to the 7D. But especially for weddings lots of low-light-no-flash situations are to be expected, so it would be a very good idea to have a full frame camera with excellent high ISO performance at one's disposal, such as the D700, D3s or 5Dmk2.
And of course you'd need lenses of appropriate quality, there's no point in having a $1200+ camera with a kit lens in front of it.

Canon EOS 7D an excellent camera. I use to own an Olympus E 510 but then decided to take my photography seriously so I purchased the Canon 7D. By far this is one of the best cameras out on the market. Of course its not a 1d or anything but the quality and features make it top rank in its class…

The camera is only as good as the person using it. You could have the most expensive camera in the market and still have horrible pictures.
These two camera's are meant for people that have already started a camera system and have the lenses and accessories in order to go to a more advanced camera body. You don't just buy a body and start shooting. Do some research and test each camera in you hands. Only then will you know which is best for you.

Hmm i would suggest for Nikon D300 its a awesome camera with lots of fetures. Some of them are:-
10.1-megapixel, large 1/1.7-inch CCD sensor for stunning images.
7.1x Wide-Angle Optical Zoom-Nikkor ED Glass Lens. Versatile 28-200mm lens ranges wide to capture landscapes, zooms in to get close to the action. In the Nikkor tradition of precision optics, the high-quality ED glass lens delivers superb color and razor-sharp results.
5-way VR Image Stabilization System
Optical VR Image Stabilization by lens shift minimizes the effects of camera shake.
Hybrid VR Image stabilization by lens shift and electronic VR.
Motion Detection automatically detects moving subjects and adjusts shutter speed and ISO to compensate for camera shake and subject movement.

You consider Canon EOS 7D 18 MP CMOS Digital SLR Camera
* 18.0-megapixel CMOS Sensor and Dual DIGIC 4 Image Processors for high image quality and speed
* Advanced HD movie mode with manual exposure control and selectable frame rates
* Intelligent Viewfinder with 100 percent field of view; 19-point,
* All cross-type AF system equipped with dual diagonal cross-type sensors
* Capture images to CF Card Type I and II, UDMA-compliant CF cards