Advice please with lens telephoto zoom choice

Hello
Just found this forum and think it is great. Spent the last 4 hours reading posts.
I am pretty much a newbie. I have a D70 and the 18-70mm kit lens and am still very much learning theory and how to use the camera.
I got a Sigma 70-300mm f4-5.6 the other day (for about $225) but after using it a couple of times I realise the limitations of shooting hand held at 300mm. It also hunts quite a bit while focusing especially in the shade. I have a tripod but not always going to be able to use it.
I want a bigger zoom lens (than 300mm) for wildlife, cricket and general holiday landscape shots that will cover everything beyond the 18-70mm lens.
I am keen on VR lens because of the better hand held ability.
The only two options I can see in Nikon is the 80-400 and the 70-200 VRs with a 2x teleconverter.
What would be the better bet?
I gather when I make my decision I should go through birddog to make the acquisition.
Any help appreciated.
Just found this forum and think it is great. Spent the last 4 hours reading posts.
I am pretty much a newbie. I have a D70 and the 18-70mm kit lens and am still very much learning theory and how to use the camera.
I got a Sigma 70-300mm f4-5.6 the other day (for about $225) but after using it a couple of times I realise the limitations of shooting hand held at 300mm. It also hunts quite a bit while focusing especially in the shade. I have a tripod but not always going to be able to use it.
I want a bigger zoom lens (than 300mm) for wildlife, cricket and general holiday landscape shots that will cover everything beyond the 18-70mm lens.
I am keen on VR lens because of the better hand held ability.
The only two options I can see in Nikon is the 80-400 and the 70-200 VRs with a 2x teleconverter.
What would be the better bet?
I gather when I make my decision I should go through birddog to make the acquisition.
Any help appreciated.