Well for me the battery is a +1, but the SD card doesn't matter at all. I like that the 13in has more display room, 1440x900, but the 11in seems to look much batter.
I am in the same boat as you but I think I'm gonna end up going with the 13" model because of the larger screen. It is only half a pound heavier and although the dimensions are a bit bigger, it isn't like I'm going to be using it while standing in line for a concert. It will be resting on tables at Starbucks and libraries. And $1200 sounds much more justifiable for a 13" laptop instead of an 11" laptop.
1. Do you need desktop space?
2. Do you travel a lot?
3. Is this your primary computer?
4. Do you use an external monitor at all?
If you're answers to 1 and 3 are yes, the 13" is a better model for you. If 2 and 4 are Yes, then the 11" is probably better for you. I personally went with the 13" mainly because I couldn't think of using anything smaller for working. If you're more on the "entertainment" side of things, 11" is probably a better model as well.
The 13inch is a more versatile option , kinder to your eyes and much more productive in my opinion. If you need a netbook to literally throw around and use for emails and a bit of browsing, there are new asus netbooks based on meego that can do that for $200 and without the added fear of losing/breaking something expensive.
The 13" is ultra portable in my eyes . It was also teh first mac for my sister ,who could not believ this is was much lighter than any of her books
I had the 2010 11" MBA (2gb ram, 64gb ssd) absolutely loved it. Really never had an issue with the 11" screen.
I sold it because I wanted to get more hard drive space and ram and had every intention of buying the 11" with 4gb of ram and the 128gb ssd
But then I realized that I can get the 13" for just $87.30 more... Now I don't know what to do.
I never attempted to use the MBA as a primary device, but I took it with me everywhere. I feel as though I would be tempted to use the 13" as my primary device which is appealing, but even though it is only 25% heavier, I still wonder if I'm going to be more hesitant to grab it off my desk whenever I'm heading out.
I think you would appreciate the screen size on the 13" for Xcode and Starcraft 2. The extra battery size in the 13" will help you play Starcraft 2 longer and I'm sure the graphics performance would be a bit better with more memory allocated to it.
Having played with both, and having own the 11 inch model since that size was released last fall, the 11 inch feels a lot smaller when you're talking a bag, carrying with you, etc. And while I have a Mac Pro with a 27 inch monitor at home, I don't find it constraining to use my MBA for the tasks that it does a good job at -- right now my Mac Pro is a room over and I'm typing on my MBA. So, personally, I prefer the 11.6 model, but it really depends on the person.