I'd definitely want the grip you are getting. Probably because I've been using winders, motors, boosters and grips on my cameras for so long. I'd feel naked without one!
Another use for the AC kit, it's a very good idea to use one when doing sensor cleaning. Much safer than using a battery, to be as certain as possible the shutter or mirror won't close down onto whatever tools you are using to do the cleaning. I got an ACK with my 10D and have used it with my 30Ds since, and will probably still be using it with 40D and beyond when I get those.
You may want to consider one or the other of the accessory focus screens. I particularly like using a grid screen, it helps with composition and to keep horizon lines nice and level. Alternatively, there is the super precision screen to help with manual focusing (usable on lenses of f2.8 or larger aperture).
Yes, I got one extra Canon battery with my 10D, and more recently with my 30D. But all my spares are "no name" batteries bought off eBay. FIrst four were $24 total, including shipping. The last two were a total of $18, including shipping. $6 and $8 apiece sure is a better deal than the OEM. And, to rub salt in the wound, they are higher power rated than the Canon OEM batts (BP511 or 511A). No problems at all after using some of them for 2 years, knock on wood.
I might try to find a BG-E2, rather than an "N". Just out of spite. $40-50 more for a stupid little foam seal strip on the door seems a major rip-off to me. No other discernible difference between the original and the N, except for the price.
Are you getting a flash or have you already got one? (I never use the built-in "fire flies".) If so, I'd want some sort of L-bracket to mount it on and an Off Camera Shoe Cord. Here, again, the new OCSC3 is 50% more expensive than the OCSC2. Not sure it's worth it, but I haven't actually compared them side by side. From the descriptions, the new one has better "environmental sealing", which sounds to me like a molded in lip to cover the flash shoe on the camera a little better. Not sure that justifies the much higher price.
Happy to help you spend your money!