stulid, I'd not even heard of CUDA until you mentioned it, and no nothing I use uses that afaik.
Seeing as the i3 has built in graphics that supports hd content (suppose most of them do nowadays?) I think I'd just get the intel i3, then if needed get a dedicated graphics card at a later date.
As we've had a 2ghz P4 1gb beast for the last 9 years, its done up proud with only the psu needing to be changed. So I expect this build will be more than sufficient for years to come, but as you say if it needs a boost then we could get the i7.
I'm not fussed that the 1156 socket will be finished with next year, they'll always be new stuff coming out, so can't keep waiting, maybe if I needed a really powerful pc, then yer I would wait for new stuff to come out.
Just having a look at the oem vs retail and changing of mobo to a different make, but it appears as you said, just ring them up and explain the situation and you get activated.
Would I need to get a cpu cooler, I can't see anything mentioned?
And i'd need some thermal compound, unless the coolers have some compound on them already?
Just need a groovy dial up modem, unless I can reuse the one in the pc at the moment, but that's not major urgent.
So copying you build stulid, I got this, just a monitor and windows 7 added, but monitor maybe changed just got to read up about 23.6" and 24" aswell as windows maybe changed to oem, bit more reading about the change of motherboard needed.