It looks like today’s shaping up to be really a really entertaining day for product announcements.

First, Canon just announced the 1D mk IV, which may finally close the lead that Nikon opened with the D3 a couple years ago. The big news with the mk IV is ISO 100-12800, with the ability to go up to ISO 102,400 in a pinch, which is more or less the same as the D3s that Nikon announced last week. If I was in the market for a new camera (and I’m not completely convinced that I’m not), the mk IV is interesting. It doesn’t have a full-frame sensor, but in all other respects it looks just about perfect.

Next, Apple’s due to announce a boatload of stuff at any minute. Current rumors suggest new iMacs, a new Mini, a new Airport base station (with multiple antennas, and maybe multiple radios), a new mouse with iPhone-like touch scroller, and some sort of desktop touchpad.

Finally, for some reason Barnes and Noble decided that today’d be the perfect quiet news day to get loads of press coverage for their new ebook reader. We’ll see how that works for them.