Great to meet another "newbie" to photography!!
To answer your question; about a year ago, I bought the Nikon D90 with the 18mm-200mm lens to start out with. Since then, I've added the 105mm macro lens (for watches ), then a 50mm "prime" as I was feeling that I needed to work on composition and "seeing" since I was getting bogged-down in the technical side of the equipment... The 50mm is used for walk around exercises: It forces me to "zoom with my feet" and get more interactive with the subject.
When Spring comes to Ontario, the birds return and the landscape comes alive again. I felt I needed more "reach" with the lenses I had, so I purchased the 80mm-400mm telephoto lens. Because of the DX sensor in the D90, this lens has an impressive effective focal length of 120mm-600mm! A "real" 600mm lens is way beyond what I can justify at this time, so this is a reasonable alternative. I'm still learning how to use it, but enjoying the practice!
As to image files and post-processing; this is where I'm lagging behind the curve. The vast majority of the time I shoot in RAW / NEF with a companion JPEG file. I use Apple's Aperture for my workflow and basic image processing, but I'm still very novice in this area.
The majority of my work-day is spent in front of the computer and I've resisted spending more time there to "develop" images. I wanted photography to be a creative outlet in my life, not to be another tie to technology... I'm trying to balance the two, and now am coming to realize that post-processing releases the potential within the RAW data.
I need to learn more, in all areas, but am encouraged by the progress I've seen in the last year.
Thanks for your compliments. Good luck in your own journey into photography! If I can be of any help, do not hesitate to ask.