Nikon D60, 70, 80, or 90?

So which one is better, and why

The D90.It is the newest and has the most powerful sensor.
the D60 and 70 are entry level… Err.were entry level cameras from 5 years ago. The D80 was more intermediate. The D90 is also older, but still is a good contender in today's market

The D90 is the latest version, so it is more up to date.
The D60 is an entry level camera and does not have an in-body focus motor, so it can't focus AF lenses.
The D70. D80, and D90 are all advanced amateur cameras with in-body focusing. Each of these cameras were quite good at the time of their release.
I own the D70, and replaced it with a D90. At present, my youngest son is using the D70.
Nikon specs for the D60, D70, D80, and D90.
http://www.nikonusa.com/...8/D60.html
http://www.nikonusa.com/.../D70s.html

Well the D70, D80 and are D90 are all better than D60, which does not have an AF motor.
D70 and D80 are already discontinued, they were good for the time they were out but the D90 is the best. Ironically, it's been discontinued too but it competes with cameras that are still out today!
D5100 and D90 would be the best options at the similar price.
Here's a DSLR Buying Guide - http://www.the-dslr-photographer.com/2009/11/which-dslr-to-buy/

Nikon D90 my first DSLR camera, but I love it! It takes very clear pictures with high resolution, it feels very durable (as much as a camera can be expected to be), the battery life is great, and the kit lense is great for multi-purpose shooting. The screen is really big and clear, awesome for viewing photos. The built in flash is good, it doesn't make photos look too bright and cheesy. There are a lot of options on this camera, and it takes a while to get used to them all, but it's easy to pick up and take ok pictures right away with auto mode, then learn the more advanced features gradually. It's pretty heavy, but I've gotten used to it and I like it. The video mode is pretty easy to use, but there's no autofocus on video though, so you have to focus it yourself, but that just takes some practice. I've used the camera and kit lense for sports photos, wildlife photos, portraits, and just random picture taking and all the photos are very clear. Overall, I think this camera was well worth the money and I love it!

Silly question. But… Know that the d60 Can't autofocus with Nikon lenses that ARE NOT AF-S.
The 70, 80, & 90 can. I had the 70 and 80, and both were good. The D60 and D70 have exact same sensor. The D80 has 10.1 megapixel CCD, not CMOS.
CCD is supposedly better in low ISO, but high ISO are pretty sloppy. Go with the D90 if you can. It has same sensor technology as D300.