Which Motherboard

[CK1]

I'm planning a new build to replace my aging Core 2 Duo and have so far come up with the following: -

CPU: Core i5 2500K
Memory: 8GB (2x4GB) Corsair DDR3 Vengeance Jet Black, PC3-12800
SSD: 120GB OCZ Technology Vertex 3
Motherboard: Asus P8Z68-V, Intel Z68
CPU Cooler: Arctic Cooling Freezer 7 Pro v2

I already have a Corsair 750W PSU, an Nvidia GTX260 rev 2, an Antec P180 case and a DVD writer so won't be replacing them.

I have four questions about my choices

1. Is the choice of motherboard a good one? I would like to get a Z68 as it seems that the P & H series are going to be end of life soon (at least according to the nice chap at Scan). However reviews of Z68 boards are thin on the ground. I would like to overclock the CPU.
2. The choice for the SSD is between the chosen one and the Crucial M4. Speeds look to be almost comparable with the latest firmware updates, are there any other considerations?
3. Is it worth waiting for Ivy Bridge CPU's as it is likely that I wont upgrade again for at least 4 years?
4. I already own a PCI X-Fi Music sound card, is it still better to use this than the onboard sound of a modern motherboard?

Grateful for any help.