I use xlcompare for comparing Excel. It creates very good diff reports of Excel features (including formatting, formulas and Macros). I often use it for simple CSV compares. Be warned, it does crash occasionally
I have used a Macbook Air 13" (i7 2GHz, 512GB SSD, 8GB RAM) for over a year exclusively for software development. The machine has been great, except I am frequently swapping windows back and forth, because of the screen resolution (1440x900).
I develop using numerous tools including Emacs, Xcode, IntelliJ, WebStorm and Visual Studio (running inside VMWare Windows 8 Pro). I have never noticed any lag whilst coding
Would I buy the same size machine again? Yes. The trade off is weight against screen size, although I think a higher resolution screen might put a strain on my eyes considering how long I use the laptop.
For me desktop was never an option, because I code on the train often. I also do not use either an external monitor nor a keyboard.
What type of freelancer, because the rates can differ by a large margin for different roles? Web designer, technical writer, developer, architect, SAP, Oracle DBA, etc.
I also find that generally, in Europe, today's rates are daily. With the assumption that the working hours are at a least the same as those of an employee; but, often expected to be one or two hours more (banks, I'm looking at you).
The legal situation in Norway is... in flux at the moment. The Snowden revelations might stop information sharing from coming in, but Norway is looking like leapfrogging Australia pretty much with data retention (along with much of Europe):
Norway isn't some magical safe haven from legal data requests. We receive law enforcement requests through the Norwegian system for mail.opera.com users (which, despite running on the same infrastructure, is operated under Norwegian law, not Australian - isn't life complex)
https://www.xlcompare.com