Who has a 2011 Macbook Air?

Hey guys, first post ever in Apple Core.

I've been looking at getting a Macbook Air, because my 17" beast of a gaming laptop (8 lbs.) is really meant to be a portable desktop, and isn't great for taking to campus during the day. So I'm not looking for a powerhouse, literally just something to get work done on (lots of web browsing, document writing, average consumer stuff)

At my local Best Buy, they have a 2011 11.6" 2GB RAM 64GB SSD that's been returned (open box) for $620 + tax which brings it to about $700 (I'm in Canada). Now, that's still a good amount of money, but it's a heck of a deal for a macbook considering I would still get a year warranty with it. My only concerns are with the lack of RAM, and the HD 3000 instead of the HD 4000) so my question to you is:

Have you ever found it underpowered? (lots of webpages open, iTunes, playing HD video, not CPU intensive tasks)

Do you find battery life to be adequate?

Is 64GB not enough space? (I keep my school files in the cloud but I like to torrent)

Is it too small to work on for hours at a time?

Is the SSD upgradeable?

Does the trackpad feel undersized?

Thanks Everyone :)