http://digitalgadgetsworld.co.uk/digital-cameras/budget-digital-cameras/blog
References :
http://digitalgadgetsworld.co.uk/digital-cameras/budget-digital-cameras/blog

"Which one is better?" — I’ll have to say the Nikon D300 is better. It has faster auto-focus, significantly higher resolution screen, better image quality, much more lenses available, significantly more cross-type focus points, weather sealed, significantly more dynamic range, significantly larger sensor, more focus points, better color depth, has an optical viewfinder, shoots slightly faster and has faster max shutter speed. The disadvantages i see here is it doesn’t shoot movies and is more expensive compared to the Lumix G3.

I found this link where you can read the user review for Nikon D300 DX 12.3MP Digital SLR Camera:
http://www.amazon.com/review/R35ZMUOTC2BREU/ref=cm_cr_pr_viewpnt#R35ZMUOTC2BREU&tag=famavca-20

You can buy it online from this link below:
http://www.amazon.com/Nikon-D300-12-3MP-Digital-Camera/dp/B000VJX7DW/ref=cm_rdp_product&tag=famavca-20

But since you seem concerned about the video feature, i’d say you should go with Panasonic Lumix G3. I found a link where you can read a user review for it:
http://www.amazon.com/review/R1HUNASKHD51MO/ref=cm_cr_pr_viewpnt#R1HUNASKHD51MO&tag=famavca-20

I also found a link where you can buy it:
http://www.amazon.com/Panasonic-Four-Thirds-Interchangeable-Free-Angle-Touch-Screen/dp/B005058BTW/ref=cm_rdp_product&tag=famavca-20

I hope this helps you make your choice.
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The D300 does take video – I have no idea about the Panasonic.

Any compact camera or DSLR, regardless of brand will only take short video clips. This is due to sensor heating issues. You normally stitch them together in post-processing for a full length video.
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The D3100 is an entry level digital-SLR camera equipped with a new DX-format CMOS image sensor with an effective pixel count of 14.2-million pixels and the new image-processing engine, EXPEED 2, both developed by Nikon, that enables the capture of high-definition images with superior image quality.

Notable Features:-
Compact and lightweight – Easy operation and take-anywhere portability

Continuous 3 fps shooting – Catch the decisive moment

Eye-Fi support – Transfer photos and movies wirelessly

New shutter mechanism – Quiet shooting, even with Live View

11-point AF system – Quick, accurate autofocus ready for the decisive moment
References :
http://amzn.to/fxh5UR

d3100 is best entry level dslr , it’s an upgrade to d3000
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The d3100 and the d3000 are pretty similar. The d3100 is a bit newer and can also take HD video. The d3100 is the d3000’s slightly "older brother." Not a big difference between the two. The largest difference is the video.

I would personally recommend the d5000 or the d90. They have both been discontinued but you can still buy them. The d90 is considered a semi-pro camera, while the d3000, d3100, and d5000 are entry-level cameras. You can get the d90 for about $900 with a kit lens, which is a very reasonable price for all it can do. The d5000 runs for about $650, I believe.
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