Laptop buying advice forum: Light, powerful laptop (no gaming)

I copied this form from another forum, but would like input from anyone reading here!

What is your budget?
1400 (I'm not really firm on this, but wouldn't mind paying less!)

What country will you be buying this in?
US

What size notebook do you prefer?
Thin and Light (13 - 14-inch screen)
Mainstream (15 - 16-inch screen)

What brands do you like or dislike?
Like: Lenovo
Dislike: Mac, HP

Would you consider a refurbished laptop?
Maybe

What are the primary tasks you need this notebook for?
Web Surfing, Office and Productivity Software, Video Editing, Computer Programming

I'm a science grad student, so I do a good bit of statistics, some image analysis, a lot of paper reading, and some special software running. The software I use is windows-based, so I'm staying away from Mac. The glossyness of HP turns me away, and I've had bad luck with Dell in the past. I have (and love) a ThinkPad T410, but it's getting up there in age and would rather not truck it around the globe with me.
I'd like to keep it as light as possible, as I'll be doing a good bit of travelling, but I also want enough power (i5 (or comparable), min. 4 GB RAM) to hook it up to an external monitor and work from it in my office. Screen resolution isn't a huge issue - I want lightweight power!

Where will you be using this laptop?
Will be used different places

How many hours of battery life do you need?
--

Will you be buying online or in store?
online or in store

Which OS do you prefer?
Windows 7

List the screen resolutions that interest you:
Standard Resolution (1366 x 768)
High Resolution (1600 x 900)

Do you prefer a glossy or matte screen?
Matte is fine

Is the laptops design important to you?
No

Approximately what date will you be buying this laptop?
Around 05/10/2012

How long do you want this laptop to last?
3 years

How much storage capacity do you need?
160 GB

Are you interested in SSD for storage?
Yes

Do you want a built-in optical drive, what type?
No