Intel Pentium 4 E Core 3.0 GHz HT Processor - $220
Abit IC7-MAX3 Motherboard - $182
1 GB PC3200 Corsair RAM - $186
Western Digital Raptor 36.7GB 10,000 RPM SATA Hard Drive - $111.25
Seagate 120 GB 7200 RPM/8 MB Cache IDE Hard Drive - $93.50
Lite-On Black DVD-Dual Drive Burner - $81
Sony Black Floppy Drive - $11
BFG NVIDIA GeForce FX 5700 Ultra 128 MB Videocard - $152
Any Case You Want - $50
Enermax 350w Noisetaker PSU - $55
Scanport 17" CRT Monitor - $80
This PC is $1,221.75 before shipping. It's all you'd ever need, including a monitor. Add $100 if you want a videocard that supports a ton of TV-Tuning, TV-OUT, TV-IN, A/V, etc. options. The current videocard will play today's games fine. Everything else is well above average.
If you're really set on spending $2,500, then of course I can make it better, but I'm saying there's no need to.
-Lasereth