Greg,
In trying to understand how Canon bodies map to Nikon's I'm told by AJ Purdy that the D70s is not comparable to the 30D. Though it seems perhaps better built than the 350D.
Nikon bodies don't map exactly to Canon bodies and vice versa. The sensible approach it is to see what x pounds will buy from either manufacturer, taking into account the whole system -- camera, lens options, future compatibility and upgradeability.
They said they considered the 30D to be aimed at the D200, but that the D200 kind of sits above the 30D, but below the 5D. I still cant really decide whether there is any like for like comparison between the models in each range.
The D200's closest competitor is the 5D.
In some ways I dont like the logic which lies behind the 2/3rd sized CCD's in the Nikon range, though I understand why it is that way. Though their offering of the DX lenses provides a solution. It seems Nikon dont plan to offer a full frame CCD so I would like to think buying into their tech and this compatible lenses would provide a reasonable investment vs lifespan (presuming Sony dont pull the rug on the use of the CCD technology).
If you want full frame you have one choice -- Canon. And if you go with Canon, you either pay a lot for a 5D or even more for a 1DS MkII. (Both are more than a D200, which you earlier indicated was getting too dear, so I assume that Canon's full-frame cameras are not contenders.)
Conversely from what I've read, there are some technical issues with the full sized CMOS in the Canon 5D.
Vignetting with wideangle lenses is the main issue with full frame, although objectionable chromatic aberration can also come into play.
It's stuff like this that has always held me back from committing to D SLR in the past.
If you want to try digital, take the plunge. Every year you wait is another year you haven't shot any pixels. Besides, if colour prints are what you're after, reasonably priced digital now equals or surpasses what you can achieve with 35mm film. (It's more complicated if you shoot slides or artsy B&Ws, but for colour prints I think the case is closed in digital's favour.)
Joe