Making the switch

First of all, pardon the cliche title. I know there are so many posts like this across the internet, but I need some genuine help here at a critical point in my life. I figured The Verge forum members were some of the most helpful, so here I go.

Here is the situation:

I'm starting college this fall semester and majoring in Computer Science. I know I don't need a powerful laptop or anything, but I want a solid machine all around for sporadic video/image editing, multitasking, casual gaming, etc. In my opinion, it's hard to top the hardware of the Macbook Air, so I'm looking at the new Ivy Bridge models. This will give me portability and a good amount of power. I'll probably go with the base 13" model but am considering the 8GB RAM factory upgrade. What do you think about that? Will I have any trouble playing Portal 2 or TF2, for example, at average settings? I'm not real serious about gaming, but would like to be able to play sometimes. Also, I've used Windows regularly since I can remember and have not been overly fond of Mac OS X after a few brief encounters with it. It seems too basic, too geared for novice users. I'm sure I can make it work, but don't want to have to put up with it per se. If I need Windows for a certain CS class I'll probably just use Boot Camp. Do you think that will be sufficient?

Now for some accessory questions. I'm planning on buying a semi-cheap monitor for my dorm so as to create some sort of docking station for a better user experience. I'll need a Thunderbolt to VGA or Thunderbolt to HDMI adapter, correct (or Mini DP?)? Obviously I'll buy from Monoprice or Newegg or something, I refuse to be 'nickle and dimed' by Apple. I also plan on buying a keyboard and mouse, but want to keep costs down. The key thing here is value. I want a good keyboard and mouse, but don't need anything over the top in terms of price or features. First thing's first, I hate Apple's mice and keyboards. So exempting those, can you give me some suggestions? I'd prefer hardwired but I guess I wouldn't mind bluetooth ones. Also, do you think I should get a normal external hard drive for media storage and whatnot, or should I go with an external enclosure for lower price and faster transfer speeds? I'd like the portability of an external hard drive, but the price and speed of the external enclosure.

Sorry to ramble on, but I really do want to get my money's worth and make the best purchases possible. Also, are there any other peripherals I should be considering? Thanks in advance for your help.