CPU, motherboard, RAM, optical drive, so far so good.
1) If this is for gaming, photo editing; then why settle for a slower HDD, when you might be better off with a WD Caviar Black (fast) or WD VelociRaptor (faster)?
2) For the moment ATI is king of the hill; for the price you're looking at for the NVidia card, you could get 2 x HD5770 and run them in crossfire.
3) You have left out one small detail...PSU?
I myself have an older (18 months old) gaming computer, I got myself a full tower case. You want your current build (and future builds) to go as smooth as possible; getting the wrong size case (eg: too small)
could turn this into a nightmare-trying to cram stuff in...but the choice is strictly up to you.
Here are a few examples of (tasteful) full-size cases.
I am building a desktop for gaming and photo editing. Here's the parts:
Motherboard: ASUS P6TD Deluxe LGA 1366 Intel X58 ATX
HDD: Western Digital Caviar Green WD5000CSRTL 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5"
RAM: Crucial Ballistix Tracer 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory w/ Red & Green LEDs Model BL2KIT25664TN1337 - Retail
I would like to go with 6GB or 8GB of RAM, but will probably settle with 4GB for now.
CPU: Intel Core i7-960 Bloomfield 3.2GHz 8MB L3 Cache LGA 1366 130W Quad-Core Desktop Processor - Retail
GPU: PNY VCGGTX285XPB GeForce GTX 285 1GB 512-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card - Retail
Sound: I will not be getting a sound card for the short-term, but will sometime in the future as $$$ allows. I will just be using some normal desktop speakers in the mean time.
Optical Drive: HP Black 24X DVD+R 8X DVD+RW 12X DVD+R DL 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM SATA 24X Multiformat DVD Writer - Retail
My biggest questions are:
Is all of this compatible with each other?
What do I need for cooling? (heatsinks, # of fans,...)
What case do I need?