Ahh I aint got 1TB in the computer, a combo of External back up drives make up my space to about 1.25TB's. 1x500GB in PC, 1x500GB external regular back up and a 250GB reserve back up.
I know its probibly over the top, but hell at least I have space. I put dvds on one back up drive, no need to hog my pc with them. 20000 Photos also take up some space

they get backed up onto DVD's as well

safe, rather than sorry I say.
Spec wise the PC is not top of the line, but it should be pretty fast and hopefully very silent as it is heavily done towards the quiet side of computing.
I also can if I want to overclock it far more and be safe, as the things going to be cool inside and in theory I could push eveyrthing for some overclocking extra power, but if that made more noise I would not bother too much. Never done overclocking before, but I now at least have the option in the future.
Still got to get some other parts together to add later, so far.
CASE: NZXT HUSH 420W Black Mid-Tower Case
CPU: (Sckt775)Intel® CoreT 2 Duo E6850 CPU @ 3.00GHz 1333FSB 4MB L2 Cache 64-bit
CD DVD: SONY DUAL FORMAT 18X DVD±R/±RW + CD-R/RW DRIVE DUAL LAYER
FLASHMEDIA: INTERNAL 12in1 Flash Media Reader/Writer
CPU FAN: Thermaltake 120mm BIG Typhoon Cooler
HDD: Single Hard Drive (500GB SATA-II 3.0Gb/s 16MB Cache 7200RPM
MOTHERBOARD: (QX9650 Supports) Asus P5K SE Intel P35 Chipset LGA775 FSB1333 DDR2/800 Mainboard w/GbLAN,USB2.0,&7.1Audio
MEMORY: (Req.DDR2 MainBoard)2GB (2x1GB) PC6400 DDR2/800 Dual Channel Memory (Corsair XMS2 Xtreme Memory w/ Heat Spreader
OS: Microsoft® Windows VistaT Home Premium (32-bit Edition)
POWERSUPPLY: 580 Watts Power Supplies (Hiper Type-M SLI/Crossfire Ready 580 Watt Power Supply)
SOUND: Creative Labs SB X-Fi Xtreme Audio 24-BIT PCI Sound Card
VIDEO: NVIDIA GeForce 8800 GT 512MB 16X PCI Express Video Card
so far cost £900
But may take it a bit more in a while with another 1GB Ram and a nice LG HD combo drive

so should end up over £1000, yes its not cheap and I could have made it myself (maybe £100 off that price) by ordering everything seperate but still not sure I could do it.
My current PC lasted 5 years, so overall year by year its not that much.