Hi
That won't be for a while

Xmas took all our money

I can however give you my impressions and summarys from the huge amount of research I have done
Here we go, im writing this in my order of preference. The D80 is the limit of my budget.
(Keep in mind I am currently un biased towards any brand and just need a camera which works for me)
**XTi**
I didn't play around with this as much. When I picked it up It felt funny in my hands. It pretty much ended there :meh: But to add a bit of weight to this 'review', I spoke to a guy at work who has one. The photo's he took looked very nice despite him using it mostly on auto mode. They had good color's and the focus was spot on. Nothing bad to say here
**D40x**
This is an entry level camera, no doubt about it. In saying that though, I don't know why people loathe it so much :meh: I liked it better than the XTi... Sure you are limited in your lense selection, but more and more lenses are being made which are compatible (and by compatible I mean will AF) and if/when you get to the stage where you need some of the older glass to AF, youll probably be at the stage where you want a new camera also and any glass you do have for the D40 will work on any other DX format nikon so no money wasted

Straight out of the box the in camera JPEG's looked as good as the out of the box shots from more expensive cameras. It is easy to use, very responsive, has fast focusing and a nice viewfinder. I felt it was too small in my hands but I can see people with smaller hands finding it very comfortable. Build quality is excellent and felt far more durable than the XTi (in reality it is probably about the same but it still felt better...). It only has 3 focus point but in all honesty I didn't notice when I was using it

I don't consider this a downside (it might be for sports and all that but I didn't get a chance to shoot sports in the store

)
**E510**
The first time I saw this was at a flower show. The shots taken looked very sharp even taken in dim/no lighting due to built in image stabilisation. Heres the guys website
http://www.digital-images.co.nz/updates?g2_itemId=4342 ...all these were taken with the E510 (or E330). The camera is nice and compact and the 2x crop factor means VERY small and light lenses...nice. The kit lense(s) are arguably some of the best kit lenses out there.
I personally wouldn't use its liveview, and it appears to turn off for a moment when focusing normally (someone correct me if im wrong). From my playing around in store, I found the viewfinder to be a little small. I heard this is due to the funny sensor size (4:3 format).
It felt more comfortable in my hands than the D40 and the XTi but not so much as the K10D or D80. My wife really liked this camera and she said it felt very nice in her smaller hands, and tis also VERY light!
The limited dynamic range which ive read about may or may not be an issue. Its easy enough to bracket exposures but if you can't be bothered...
**K10D**
I was this >< close to chosing the K10D over the D80. The build quality is excellent and the weather sealing puts this well above is price level. Image quality is excellent and hard to beat. Some of the people I asked for opinions own the K10d and a bunch of high end nikons. They said if you can get the shot with the K10d, its hard to beat the results with anything else.
Alot of the reviews really hammer the K10d for the soft in camera JPEG's. While this may be the case, I didn't notice anything and neither do any of the more seasoned users. There are a few tweaks you can make to fix this if you want, and if you shoot in RAW this won't be a problem anyway.
In camera IS is nice and means you can use the huge majority of the old pentax lenses including the limiteds and gains its advantages.
With Pentax, you are buying into thier phenomenal lenses. I hear the limited are on par with Zeiss but can be hard to find.
Button layout is superb and while it may look cluttered, i found it easy to use as soon as I picked up the camera.
Focusing was very fast and spot on but focus tracking was lacking. This is the main reason I didn't choose the K10d. The other reason is the flash system. Nikon's is the best hands down, pentax's isnt
The other little quirk is inconsitent exposure.
The K10d would of been my choice for its excellent image quality if it was only landscapes I was interested in when I had time to compose, but there may be the occasion where I need good focus tracking, eg wildlife, sports etc. The K10D can't track much more than a toddling baby

(ok maybe thats a bit of en exageration but its not good :mrgreen: )
The camera felt very good in my hands and it is nice and esy to use. The extra weight over the D80 is hardly noticable.
**D80**
Im in love

I wont go into this one other than to say read the comments on this forum and any other forum. I think youll see why I chose to save for it
Hope this helps! Sorry its so general. All these cameras are good for different people. These are purely my opinions from a short amount of time playing with them and a huge amount of time reading
I have lots of comments from users of the K10d and a few from the E510 if you are interested.