I've read all four pages of this and I still can't keep everything straight...  I do know I can't really afford Octane though...  So I am looking at Reality/Luxrender and wondering if it would suit my needs.

I don't really do high res images because they take so long.  I know that resolutions keep going up and I'm going to have to get used to the idea of doubling the resolution I render at.  One of my current projects is taking about an hour per frame, and that's just unacceptable to me for stills and makes animations unthinkable.  I am happy with Firefly's output, but not the long render time.  Most people seem to be looking at other renderers because they are more physically accurate, I just want results similar to what I'm getting now in a fraction of the time.  Would I get more benefit going from 4 cores (using 3) to 8 cores (using 7), or should I put the money into a beefier GPU?

I was looking at the GTX 660ti, even though it was mentioned above that it is a less than ideal card.  Does Luxrender take advantage of an SLI setup?  Would two 660ti cards compare to a gtx 670, or would that card's higher RAM be more useful?  I'm assuming that two 660s would still only give me 2GB usable memory as each texture would need to be sent to both cards?

This is almost too much for me to keep track of...