Bootstoo said:I like my D300. The guy at the camera store assured me that the D7000 was twice the camera the D300 is. Better resolution.
I have the D7000, and I love it to death, but it's not 2x the camera of the D300 or D300s. The only reason I went with it over the D300s is the slightly better low light performance and slightly better video performance. In decent light and/or flash, the D300 and D300s are screaming good cameras.
Now, to buy one used? A refurb will give you a 90 day warranty at best. A brand new D7000 can be had for less than a refurb D300s, and you'd have a longer warranty. If you don't need the ruggedness or frame rate of the D300/s (and it sounds like you don't) then the D7000 would be a good choice because of it's price right now, NOT because some daft sales person told you it's 2x the camera.
It's not as "pro" as the D300 but it handles very well. It is smaller in the grip and lighter than the D300, so that might be a put off. There might be a switch or two more on the D300 that gives you a shortcut the D7000 lacks, but it has some handy features missing on the earlier bodies. (U1 and U2 saved user settings for example)
Another option is to look for a used D700 - they can be had on Craig's List for example for $1500 or less and they are amazing. (think: D300's big brother) No video though.
You would probably be happy for years to come with a D600. It will use DX glass at 10mp, which is fantastic for everything but huge prints (despite the warnings posted above). Heck just a few years ago 10mp DX was state of the art...