The total for this build comes to $1601.89 and includes a lot of highend components that are quality brands and will give top performance. You can go with less expensive parts as that is your choice to do so and with the fourth of July sales ready to hit you should be able to get some of these components on sale. You will be able to do both overclocking and SLI with this build if you choose to do that.
To use the Apple monitor with the Thunderbolt port you will need a mini displayport connector and you can either get a displayport cable with a mini display port end or an adaptor. The GTX 670 has a display port connection and has support for up to 2560x1600 resolution.