[Build Help] Time to finish my build, last minute questions

Last summer my old computer finally gave in after 7 years. I were hoping it would last a bit longer, for a lot of the new tech to come. So I decided to build a kind of temporary PC. Now the 680 is finally here, and I got the money to finish it. I will be using some of the parts I got already, and need some help deciding on the rest. What I got:

Case: Fractal Design Define R3 Black Pearl (Big tower)

CPU: Intel 2600k (with after-market cooler)

PSU: A Corsair TX750W

Soundcard: Asus Xonar Essence STX

Storage: 1TB HDD and a small SataII SSD to be used in RST, 500GB external

The rest is going to be used for another computer. So I'm obviously missing some parts here. What I were thinking about until recently:

Motherboard: ASUS P8Z68-V PRO/GEN3

SSD: Samsung 830 256GB

GPU: The 680

1. Is it worth waiting for Z77? Or will it not mean much for me, since I am sticking to a single 680 and the 2600k for a long time? Also stability etc.

2. The SSD. I am getting 200-300 GB. I saw some benchmarks though, which suggested you get a great boost from doing a RAID0 setup. Which I have previously been told you don't, leaving me confused. Since a random guy told me one, while the other were benchmarks from a review site, I'm inclined to believe it does work, but would like confirmation before I get two 128GB instead. (Got nothing important on them, other than programs, games etc, which are easy reinstall. Important projects, documents gets backed up on the HDD and the external HDD. So the stability isn't that much of an issue, more an annoyance should it occur.) But since TRIM doesn't work in RAID, does it mean I should get a SSD which got another way dealing with the problem? (Don't think the Samsung does, if it does, that would be great.) The benchmark with the SSD were done with the M4, does it have an alternative for TRIM that would work in RAID 0?