First of all, nice choice! We can DEFINITELY bring that total down to a much more reasonable figure.
*A rechargeable lithium-ion battery pak - $70 (extra - the kit comes with one)
I do strongly believe that you need multiple batteries. I've got 4. And you know what? There have been days when I've needed all 4. Generic batteries are dirt-cheap.
http://cgi.ebay.com/Two-LP-E8-Battery-Canon-EOS-550D-Rebel-T2i-Kiss-X4-/290458212359?cmd=ViewItem&pt=Batteries_Chargers&hash=item43a0a89807
I've heard a rumor that the generic batteries overheat faster than the expensive Canon batteries. I have no information that could confirm or deny this assertion. I've definitely had to wait, on numerous occasions, while my camera cooled down. Then again, I shot half of my movie outside, in 100 degree high-humidity Richmond summer. My inside shoots have never encountered any overheating.
*If I plan on HD video (I certainly AM, you dweeb): Two ScanDisk Extreme III 16GB Secure Digital High Capacity Memory Cards - $170 EACH - $340
Wow, that's expensive. Are those SDHC, or SDXC? You don't need SDXC. I've got friends who are using class 6 cards, and they say that's fast enough. My Transcent class 10 16GB card didn't cost me that much more. I've been using this one, and it's done it's job nicely:
http://cgi.ebay.com/TRANSCEND-SD-HC-SDHC-CLASS-10-16GB-16G-16-G-GB-MEMORY-/300395421193?cmd=ViewItem&pt=AU_Electronics_Memory_Cards&hash=item45f0f65e09
*A 55-250 mm f/4-5.6 Telephoto Zoom Lens - $300
I think I might recommend scratching that one off your list. For narrative work, a telephoto lens like that won't come into play very often. You are definitely going to need wide shots, and the 18-55mm kit lens will take care of that. I don't own one myself, but based on stuff I've heard, from people who's opinions I really trust, if you were going to buy ONE additional lens, a 50mm prime is the way to go, and you can get one for $100.
Why would you get a 50mm, when the kit goes as far as 55mm? Well, your prime lens will have a much lower f-stop, and you'll get some really crisp footage from it. Also, make sure you get an EF-S lens, not EF. That pimple-faced kid might not know the difference, because you can fit both on the T2i, but with an EF lens, you've got to do some math to figure out what the image is really going to look like.
*A DigiPower Lens and LCD Screen Cleaning Cloth - $6
These little things are cheaper, more usefull, and quite handy:
http://cgi.ebay.com/Lens-Cleaning-Pen-Clean-UV-Canon-Nikon-Pentax-Lens-/130416511332?cmd=ViewItem&pt=Digital_Camera_Accessories&hash=item1e5d6e0964
*A 3 foot HDMI cable (I have no idea what the fuck that is for) - $9
Yeah, it's only $9, but I don't think you need it. A lot of people are connecting their T2i to HD monitors, but if you wanna go that route, you'll probably end up spending $2000 just on your camera mount and accessories, not including any lenses. I see no occasion in which you'll want to connect your camera to your TV.
I think I'd start out with a less expensive version of Vegas. You don't need all the fancy stuff you'll be getting with this more expensive version. A few years from now, you can consider stepping up to something like Premiere, but for the time being, straight cuts, with a small amount of color correction is all you'll be doing, and Vegas Platinum ($99) will more than do the trick.
http://www.sonycreativesoftware.com/moviestudiope
Edius Neo 2 is also an option, and worth considering. It's one of the very few (along with Sony) editing suites that can handle T2i footage in it's raw form. I think it retails for something like $130:
http://www.grassvalley.com/products/edius_neo_2
Gadget Bag kit for the Camera: $65
Mmm, I think those are for photographers. Just be gentle with your camera.
One thing you're missing -- a good tripod. I'm going to dispense giving too much advice on tripods, as my most recent purchase turned out to be a pile of crap. Total waste of $100. You definitely want something sturdy, and a fluid head would be nice. I've heard you can purchase a good fluid head in the ballpark of $30 on ebay, and put it on a modestly-priced $100-$150 sturdy tripod.
Oh, and lastly, you can chop $300 off your total, if you don't mind using the Japanese version of the camera. You can get the Kiss X4 on ebay for $100 less than the T2i. Since you'll be buying on ebay, you'd have to let go of the extended 4-year warranty you were planning on getting, so I guess that's your big decision. How secure do you feel about taking good care of your toys? Just be gentle with it, keep it away from kids, moisture, etc. The Kiss X4 is the EXACT same camera. Except, have you been boning up on your Japanese? Cuz that's the language the manual is in. Or, you can download the English manual in PDF.
http://cgi.ebay.com/Canon-EOS-Rebel-T2i-550D-Kiss-X4-EF-S-18-55-KIT-NEW-/120602388835?cmd=ViewItem&pt=Digital_Cameras&hash=item1c14766963
