Hi,
Sorry to enter the thread so late but I hope this helps.
Firstly, I note from your shortlist of camera that you have a mix of SD and HD equipment. I think you need to decide which you plan to go for. I went for HD - there are advantages and disadvantages of this approach. The advantage is that, done properly, the footage is really nice and HD itself is future proof. The disadvantage is that HD videography is (more) unforgiving of errors and inferior quality optics. For example, a slight focussing error will be more evident on an HD movie (because the rest of your movie will be pin sharp); also, not all lenses are of a quality which will make the best of HD.
There is no doubt that the 5D mk2 and 7D are excellent cameras. I am thinking of buying a 7D as a backup to my main camera (see later) but I see some early adopters have been stung by overheat warnings on this camera (see
http://www.dvinfo.net/forum/canon-eos-7d-hd/458260-overheating-warning-icon-mild-temperatures.html). But these cameras are not a substitute for a purpose built HD camera - the way the controls are laid out, unlimited capture (providing you have enough tape), XLR audio inputs, focus and zoom presets and many other factors mean that SLRs still have a way to go, although there is no doubt the technologies are converging.
So, I would advise going for a dedicated HD camcorder, e.g. Canon XL-H1A and consider using a 7D or 5D Mk 2 as a second camera. You can use interchangeable lenses on both although the 20 x zoom on the XL-H1A is excellent in its own right. But it's nice to have one canera set up for wide (scene setting) shots and one for the birds. There is some rumour that Canon may bring out a successor to the XL-H1 series but I don't know much about this.
Regarding accessories, the number one priority is to buy a decent tripod and head. Most still camera heads are no use. You will need a fluid head for smooth pans and tilts. Expect to pay minimum $1000 for this - there is no point having shaky video on an expensive camera. Also, if you go for the XL-2 or XL-H1A you will need the Canon EF lens adapter (approx $380). You may want to consider buying a shotgun microphone and wind shield. I have gone for the Sennheiser ME66 / K6 combination with Sennheiser foam windshield and a Rycote windsock to prevent wind noise ($600 approx).
For editing I am using Adobe Premiere Elements 4 (since replaced by 7) which seems fine for my purposes, but I'm considering upgrading to Adobe Premiere CS3 (which is several hundred dollars more expensive).
Hope this helps,
Neil