Ok, well I don't have that much expierence since I have only been shooting with a DSLR since November but I will offer my insight as to what I have seen.
I have shot with Canon (350D) exclusivley and I love it, wish that I had a few more features but alas this is the price you pay when jumping in and learning. At Drift Fury I shot a couple pics with Tom's D70 and I will admit that the camera felt good in my hands and from what I could tell colors were great. Nikon does have a vivid color mode that really makes the colors pop as compared to Canon but both cameras have their good points and drawbacks. For a more in depth look you can go to
www.dpreview.com and find a complete break down of the camera you are looking into getting.
Now as for my camera, I love it and have a blast shooting with it but the lenses (read L glass) is a nightmare price wise but can produce some of the most stunning photos I have ever seen. Now if you can get the 30D for $700 then we need to talk cause that is what I need. LOL. Now I jumped into the DSLR world cause of the entry price of the camera and a hook up from Jaime on some lenses. Now with having the 18-55 and a 70-300 I started out pretty good but after a couple of weeks of shooting, you realize that you need/want better glass and that is when you start hurting because the price of the good glass ("L") is a min. of $500 and as high as $15k but this is the price you pay to play with the big boys. Now you have to ask yourself what it is you are going to do with the camera? If you are just going to be shooting stuff for yourself then maybe a high end point and shoot is all you really need, but I know you want a DSLR
My ultimate dream set up is a Canon 1Ds MKII with a Canon 24-70 F2.8L on the camera and a 1D MKIIn with a 70-200mm F2.8L IS mounted on it as a back up.
Both are user friendly with some options on the camera and some buried. Really depend on which one you have used before but since you shot Sony it will be a brand new world all together for you. My suggestion is head to Wolf Camera and play with each one and see what feels better in your hand and easiest for you to understand.
With a DSLR, you are going to get that feeling no matter what because you are going to run into an instance when you need a longer range, a lower F stop, etc, etc. The camera bodies are expendable but the Glass is what is the most crucial part of the equipment you buy.