The dual 2,7 is a good bargain at the moment and still has the pcix slots if you need them.
DEFINITELY buy RAM and a second HD from someone else than Apple. Way overpriced stuff, but go with Crucial or some other brand RAM. (I’ve ended up with only Crucial after some non-brand problems). Samsung should be good, too, as that what Apple is mainly putting in.
For uncompressed work I’ve built an external SATA RAID in a PC-Box with the Rocket RAID 1820A card as a basis. 8×400 SATA disks makes the world spin faster. And an internal 2×400 RAID…
If you’re picking up a second hand machine, get one with eight RAM slots and as many PCIX slots as possible. (This differ a bit from model to model)
And get a good videocard if you’re working with motion. (I think Shake also is affected by this)
An advantage with the PCI-E macs (apparently) is that some of (or all) the rendering – not only previewing – in Motion is done in the GPU.
That’s worth a lot of hours, if true.
Apparently the 7800 GT is the best price/performance buy. (And it doesn’t steal two of your precious PCIE slots)
If possible, I’d buy the quad. My experience is that buying the “top” machine gives a considerable longer lifespan that more than pays for the extra $$$.
Gunleik
(Formerly owner of SE/30 – / 9600 / B&W 400 1st ed
Currently running a Dual G5 2Ghz 1st ed/6 GB RAM/FCP studio/Cubase SXC3 + a TiBook 667/100Gb HD/1Gb RAM)