Online gaming is fun, but make sure it doesn't effect your studying - which is much
As for the system, Athlon XP2500+ (1.83GHz) 333fsb will do the trick. This CPU has extreme overclockability, upto 2.4GHz
Nothing fancy like Corsair, just get a stick of 512MB DDR400.
Get yourself a 128MB Radeon 9600 Pro/XT.
RAIDMAX Black 10-bay Case with 420W Power Supply
Rosewill 52x32x52x16 CD-RW & DVD Combo Drive, Model C523216, Retail $39.99
AMD Athlon XP 2500+ "Barton", 333 FSB, 512K Cache Processor - Retail $80
Maxtor 40GB 7200RPM IDE ATA133 Hard Drive, Model 6E040L0, OEM Drive only $53
Mushkin Basic Green 184 Pin 512MB DDR PC-2700 - Retail $77
ASUS "A7N8X-X" nForce2 400 Chipset Motherboard for AMD Socket A CPU -RETAIL $71
POWERCOLOR ATI Radeon 9600Pro Video Card, 128MB DDR, 128-bit, DVI/TV-Out, 8X AGP, Model "R96-C3G" -RETAIL $124
All above from newegg.com.
Now just minus anything you don't want.
Best I could do.