Nikon Rumors is reporting that the D3200 will be announced within the next 24 hours, with a 24 mp sensor. This is, of course, a Rebel equivalent.
Canon likes to hand down sensor technology from the top of the line (7D) to the lower levels. Nikon seems to be less concerned about that. Honestly, I'm not excited about a 24mp sensor (I'd rather Canon stick with 18-20 mp and improve ISO and dynamic range), but given the rave reviews that the D800 seems to be getting, it will be interesting to see how this 24mp sensor performs in comparison to Canon's current APS-C sensor.
Competition is good, so it will be fun to see how Canon reacts. I don't anticipate a new 7D until Photokina. This will give Canon at least four months to dissect the new Nikon sensor and figure out how to best it. I'm hoping Nikon has really raised the bar.
I can't wait to see how much APS-C sensor technology has advanced since the release of the 7D nearly three years ago. This new Nikon should give us an idea about that.