For CPU, so long as you're not planning on doing anything more than the Revel T5 stuff, anything from an i5 upwards should be more than sufficient. I'd lean towards one of the newer i7's to reduce the time between upgrades. It's why the AMD build is likely to also be fine (though, I'm not sure about compatibility - I'm really out of touch when it comes to AMD).
At a guess (they change so quickly and it's been some time since I've gone shopping), anything from a 650 upwards would do you fine. (I personally use a GTX 760) You wouldn't need an expensive card like a Titan. It'd be expensive overkill.
As for the HDD, 120gig might constrain you a little. I used to have an 80gig SSD (operating system and programs) but I was always struggling for space on that drive. I currently use a 250gig SSD with 4 mechanical drives setup for a raid. I doubt you'll need that much space. Some of editing projects I've worked on take up over 1TB of space.