I was in a similar position to you, sold a D300, 70-200vr, 16-85vr and 70-300vr to buy a GF1 with 14-45 and a samsung compact superzoom.
My reasoning was that I didnt enjoy taking all the Nikon gear out on day trips and holidays. It got in the way, every trip was a photo trip instead of a holiday.
I soon sold the Samsung because it just couldnt cut it.
Anyway, to cut a long story short, I ended up buying a Leica X1 and some Micro 4/3rds gear.
The Leica is superb and goes everywhere with me. I enjoy using it, even though it has a fixed lens and not the quickest AF.
Unfortunately, the IQ of the Leica showed the M43 gear up and I used it less and less and started to miss a long zoom and the IQ of my D300.
So, not being able to afford another D300, I bought a used D200 and a couple of lenses, one being an 80-200 f2.8 ( this is what I really missed)
It was a long expensive process, it would have been cheaper keeping all my Nikon kit then buying the Leica!
So, think very carefully about selling the D300. You are going to miss it, but only you can tell how much. Switching to a lesser Nikon may be the best idea. I love my D200, its almost as good as the D300 was and using the Leica made me realise that I just really need basic settings with cameras. I never used all the D300 had to offer.
Dont underestimate the quality of the older Nikons though. I got a request a while ago from Getty to licence some of the images I took with a D50! They didnt want my D300 stuff!
Allan