aleksanderdev :
Titan is for multimonitor gaming.
690 If you need to use nvidia not amd
7970 SLI BEST CHOICE for singel monitor gaming
What a bunch of nonsense
Anyways OP, CF 7970s is substantially faster in all the games it works (a small handful of games don't work well with crossfire - browse through
TPU's review for examples).
Basically it's your choice - do you want to have a faster setup that can be finnicky with drivers and may need to use framerate limiters to avoid stutter (7970 CF)? Or do you want a slightly slower setup that has no complications (GTX Titan)?
If you're talking about a single 1080p screen, I'd say get the Titan, as nothing is even close to needing more power than the Titan offers at 1080p. If you're talking about a single 1440/1600p screen, the extra speed of 2x7970s may come in handy and be worth consideration.
I'm guessing that since you're new to this and since you're already OK dropping cash on overpriced parts (the 3970X), the Titan is absolutely the card for you.