Advice on nikon vs sony vs olympus dslr please

I'm shopping for a DSLR camera… My first after using a megazoom for a while. I'm considering the Nikon 3100 (seems to have solid features and get good reviews).
http://imaging.nikon.com/...slr/d3100/

but I loved my Sony, and I'm wondering if there's a sony dslr of comparable quality and price to nikon 3100… How about this one for example? Http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10151&catalogId=10551&langId=-1&productId=8198552921665345641 If I understand correctly, it has good zoom capacity.

Someone also recommended Olympus E420 http://www.dpreview.com/...use420.asp
Does anyone have knowledge/experience on this? I need some advice about image quality, user friendliness for an inexperienced dslr user, macro capacity, zoom, etc. If it helps, my photography is 90% nature and landscape, 10% sports.
Thanks so much

Added (1). Thanks so much for your replies. I have since discovered that the Olympus E-620 has better built in stabilization than the 420 and is generally an improvement over the older model. I'm now basically torn between the nikon 3100 and the Olympus. Any final advice?

The Nikon is the better of those three.

Any DSLR body is a fine tool to use to make great pictures. Macro, zoom and what you use it for is up to the lens you buy. I can't tell you which one you will like. You will have to go to the store and play with them or do some serious research. Cameralabs.com has walk through tours of almost every camera to date.

Don't let fanboys talk you into any brand you might not like. It's your camera, not how some internet people feel in in their pants.

Macro and zoom capability are dependent on the lens(es) selected, one of the advantages of owning a DSLR camera and al three of these brands have a good selection of lenses. The Nikon brand is one of the most popular brands sold but i believe Sony and Olympus offer better values for the $$.

The Nikon 3100 is a brand new model while the Olympus and Sony models are no longer manufactured and/or have limited availability. However, the Olympus E620 which is a comparable model to the Nikon has a number of features that make it very attractive although it does not have the capability to shoot video that the Nikon model includes. Particular advantages of the Olympus include a larger viewing screen with tilt and swivel features that are great for shooting at low angles and awkward locations when using the Live View feature. It also has illuminated control buttons that make it easier to see and adjust settings in low light. I also prefer the in body Image Stabilization (IS) feature of most Olympus and Sony models over the Vibration Reduction (VR) system used by Nikon. The VR system is incorporated into certain lenses while the IS of Olympus & Sony applies to nearly every lens that can be mounted. I prefer the IS system because it means that there are less complex electronics and fewer delicate systems that can require adjustment in the lenses making lens designs simpler and less likely to need repair/replacement. This also gives the photographer more control over the decision to use the feature without being concerned about what lens is mounted on the camera.

A Sony model that is comparable to the Nikon is a little bit harder to identify because Sony has a very rapid product upgrade cycle but the Alpha(A)390 would be a fairly comparable model that is available now. Like the Olympus this model doesn't have the video capability but does have in body IS (called "Steady Shot INSIDE" by Sony) and a tilting view screen (but not the swivel feature of the Olympus).

One note about Sony cameras, they have several models with "Translucent Mirrors". These are immovable mirrors that work something like one way mirrors that appear to be glass from one side but a mirror from the other side. While they reduce vibration and noise, this type of camera has been attempted before and never been very successful and I would avoid these models for two reasons 1) the mirrors "split" the light thus reducing viewfinder brightness and diverting some light from the film/image sensor and 2) they have proven to be very delicate and difficult/expensive to repair.

All of these models have dust reduction but the Olympus version is widely recognized as the best dust reduction system a function which they developed and patented before anyone else included it in their cameras. In general I would say the Nikon would be the best choice for shooting very high speed sports action, the Olympus would be the best quality for the $$$ (their optics generally are the among the best available) with a slight edge for nature photography while the Sony would get the best marks for easy to use interface and is a good overall camera.