Couple of things:
I don't think Intel plans to release a 6 ore 8 core processor on Haswell's desktop socket, but you're probably not going to have a use for more than 4 cores in a year or even two if you don't have a use for them today.
I have an AMD Opteron 165 running a 50% overclock (1.8->2.7) and it has been rock solid for 6 years. You may be reducing the life of a chip by overclocking it, but for most processors it's something like cutting the lifespan from 30 years down to 20. You're probably not even going to find it useful in 5. Add to that, there isn't really any such thing as a stock voltage or clock on Sandy/Ivy because of turbo and c-states, thus the frequency and voltage you run it at is completely arbitrary. Intel says "stay under 1.5v". Well, I am - I'm running 4.5ghz with 1.25v, which is approximately "stock" voltage and considerably below what Intel defines as the safe upper limit. Voltage is what typically kills a chip, and I'm not running any higher than stock, so I could perceivably get 20 to 30 years out of my chip at this clock. It's your choice not to overclock but the performance is there, for free. Intel even provides a Windows-based utility that lets you easily change what it turbo's up to with a single click.
That said, if you're not overclocking, the 3770K is not a bad choice. It has the fastest "stock" clocks (and highest turbo overclock) of any chip Intel sells and it's very easy on the power supply. It's faster per clock than Sandy and since you're not overclocking, you wont experience any of the negatives. In fact, you'll probably gain a non-negligible amount of performance from this upgrade. Also, you probably won't be using more than 250w under full load, even with a 670, because of the power savings this generation.
As for the motherboard thing, I don't believe I can say that Intel makes the most stable motherboards when it's unstable at the same overclock that another board is stable at. Intel motherboards are just Foxconn boards with an Intel sticker on them anyway - a company that is widely regarded as "entry-level" and "budget".
EDIT: Not everyone is aware but even the non-K chips allow their turbo frequency to be increased by 4 bins. A 3570 (non-k) can turbo at up to 4.2ghz.
If you are not overclocking, stop buying K processors, just extra wasted money. I think you made a wasteful decision in the end. You should have just stayed with your 2600k setup, banked the cash and then went with the nvidia 700series and haswell.
OP care to tell me when you maxed out that 16GB of RAM you had, and if as I suspect you actually didn't can you explain why you would need 32GB?
Current build:
Cooler Master "Cosmos 2" ultracase
Intel core i7 3770k @ stock speed (Ivy bridge)
Intel Extreme systemboard DZ77GA-70k
32GB of DDR3 XMP1600 Corsair Venengance (4x8GB)
PC Power & Cooling (OCZ) MKII silencer 950w (1000w rated) single rail/Active
2 x EVGA Geforce GTX680's 2GB in SLI
2 x Western digital 6gbps SATA III 64mb cached RAID'd 1Tb drives
Samsung 830 SSD 256GB for OS partition
HP lightscribe DVD/CD multilayer burner SATA
LG Bluray and Bluray XL 128GB 14x burner SATA
My previous system was:
CoolerMaster Stacker 832 case
intel core i7 2600k @ stock speed (sandy bridge)
first release intel extreme sandy bridge motherboard
16GB of Corsair Venengance 16GB DDR3 RAM
2 x Wesgtern Digital 1TB SATAIII 64mb cache 6bps harddrives (RAID'd)
BFG Powersupply 800watt
HP lightscribe DVD/CD burner
EVGA Geforce 580GTX SC
if you plan on playing bf3 multiplayer get the 3930k, otherwise the 3770k.
I see you have the 2600k, I have the 2500k, both are "k" parts...IIRC there were more than just clock speed differences between the K and non K like HT and virtualization?
You are correct, I do use the superior processor brand.