Girlfriends mom needs a new computer... Need some help

[googz]

So the lower end non gaming stuff is a bit foreign to me. Looking to build her a simple, cheap PC for web, email, word processing and possibly online movies and shows. I'd really like to go with an I3 and stay away from AMD, but that's still an option at this point. Really want this to be something we can work with for years to come doing simple upgrades as they're need. Might try and set this up on her 32" TV, but would have to just see how it would look and if she would even like that.

So what I need is:

CPU: I3
MOBO: video support (with dvi), usb 3, sound
Memory
PSU
HDD: 500g should be more than plenty
Case: something small, possibly even horizontal, but still having enough room to last years. USB 3 on front

[Diesta]

I think you need to run with an ivy bridge build for native usb 3 support (without third party hardware put on the mobo)

[yurano]

At that point, its probably cheaper to buy prebuilt. You can get one of those tiny HTPC computers for $300 with a keyboard and mouse. You're not going to be able to top that going custom. An OS and a 500GB HDD would already amount to half of $150.