If it had been released in 1996 it would have been ahead of its time, but I'm afraid these systems are just standard HTPC systems, albeit higher-end ones, and quite nice looking too. They're certainly nicer looking than most HTPC's I've seen.

As far as RAID and SSD's go, your CPU will be the bottleneck. The (approx) 40% speed improvement is on read/write operations to the hard drives. Loading applications will be faster, transferring files will be faster, and you will have the capability to capture uncompressed HD video without dropping frames. If you perform a lot of large file transfers from drive to drive or system to system, then you will really like the benefits of RAID. However, if you have a script processing at 10fps then it will still process at 10fps because that's as fast as your CPU can do it.

If you're happy with the performance that the Q6700 brings then that's really what you should get. Motherboard upgrades are not possible in these VGX-XL systems due to the custom form-factor they use, which is a shame because if you could change the motherboard then you could increase performance dramatically for relatively little cost. I'm not convinced a faster GPU would make much of a difference, but of course if you play the occasional 3D game, and/or want to just tweak your system to the max then certainly there is no negative impact, provided your case cooling is adequate. ;)

An observation about overclocking, its interesting how it was once a risky, warranty-voiding endeavour for the cash-strapped and MHz-hungry and these days its used as a marketing gimmick and can actually cost more to implement effectively than just buying a faster CPU or GPU in the first place!