Thom Hogan
Thom Hogan has some interesting thoughts on full frame [35mm] vs. APS-C. See:
www.bythom.com (Bottom line - most of us drooling over full frame won't ever see the difference. Money would be better spent on glass or, even better training in photography. It ain't yer tools - it's your talent [or the lack thereof])
I am lusting after the D700, but suspect that reality ($$) will keep me with my D200 for another year or two. The one exception might well be a serious, paying portrait/wedding business. That is perhaps the only area where a full frame and hi-res sensor might make economic sense.
(Nikon) Cameras to consider:
-- There are still some refurbished D40 deals out there. Not many, but there is a strong argument that the D40 is one of the nicest cameras that Nikon ever made. (Ken Rockwell goes nuts over this box.
www.kenrockwell.com (N.B. Many photographers cough blood, or worse, at the mere mention of his name.)
-- Beloved Spouse bought a D60. Smaller and lighter than my D200 - fewer features, but the images are the same or better. That said, the conventional wisdom is that it will be replaced by a "00" model soon. I took it on a trip to the east and was very pleased. Small body is nice, but most of my lenses are fairly big, so much of the advantage is lost. If you really want something small, you are probably better off considering the various Olympus lines as they have smaller lenses as well.)
-- Son in Law has a D90. Less rugged than my D200, slightly better images. Is the extra ruggedness of the D200 (Now D300) worth it, even in Africa? Who knows? I suspect not.
Spend some time at
www.dpreview.com and then flip a coin.
The good news is that whatever you buy, even Canon

)), your camera will take better pictures than you can.