$2000 i7 computer

"Is it worth it to pay $25 to get RAM that runs at 1600MHz?"

Not really. You can always OC your 1333 to 1600 easily.

You will need a aftermarket heat sink fan if you want to OC. I recommend the Xigamatek Dark Night.

is there any reason as to why i should get a corsair PSU? i was thinking of going for the cooler master case when i was making this build but i think that im going to stick with the antec case because it looks nicer and has better airflow

Considering your future plans, I'd opt for a better PSU. I put the Antec Signature 850 in my 1200 cases. The Corsair HX series is an equivalent which I'd use in an HAF 932 if the client wanted a more aggressive case style, but w/ the Antec case, I think the Signature is the better choice. The Corsair TX and Antec TP series are next level down.

The 640 GB Black's are not among the top performers though the 2 TB model is. Check the performance charts here making sure to consider temperature and sound:

http://www.tomshardware.com/charts [...] ks,50.html

For Photo Editing or CAD work (if that includes rendering) you will want to avoid a TN LCD panel. Best choices, though they will put a damper on your budget, are the Dell 2408 S-PVA panel and it's successor the U2410 H-IPS panel. Both will give you 1920 x 1200 as oppossed to 1920 x 1080. I like the extra real estate at the bottom of screen as playing at 1920 x 1080 leaves me access to task bar and other goodies. The 2408 WFP runs about $440, the 2410 can be had for $480

http://www.fatwallet.com/forums/hot-deals/951859/

As for the GFX card, if you talking XMas time, I'd hold off a final decision until I see what nVidia comes up with around turkey day.