1. Don’t buy extra RAM from Apple. Buy it from Crucial, or Other World Computing… it’s less expensive and quite good.
2. Probaby the sweet spot in pricing is the 2.66… the 3 gig machine will only be about 13% faster and only for renders and encoding… lot of money to pay for that bit of speed. (a power user would want it, but…)
3. Start with 2 gigs. if you find that it starts doing a lot of disk caching, or you want to run Motion a lot, then add ram as needed. You’ll know when you start disk caching instead of RAM caching.. it will slow down a ton. State of the Art hardware costs more always… get used to it if you intend to run state of the art. I don’t think your RAM needs to be 667MHz DDR2 ECC fully-buffered DIMM (FB-DIMM) memory. If it is this it should work, but has to be installed in matched pairs.
4. Buy at least one more internal drive with it for media storage. Don’t count on using the startup disk for this. Post what format you intend to start editing, and we can give you some help there… HD requires a lot more speed drive wise than HDV or DV would for example.
5. Buy a mac. You’ll never look back.
Jerry