Rock Band 3, due out this holiday, has a “Pro” mode that lets you play using an actual electric guitar, while being scored playing actual guitar tablature.
It’s like my dream come true! Back in college, I spent an unseemly amount of money on a Fretlight guitar after seeing one at the Experience Music Project. It’s an electric guitar with LEDs underneath each fret, which can light up to demonstrate fingerings. The trouble was that the software sucked. It showed scale patterns and chord progressions, but there was no validation that you were doing the right thing nor sense of progression.
Now I can channel my unreasonable urges to master video games into the skill of actually playing guitar. Oh, please, be as awesome as I think you are.