This PC: Sh--. P4 2.2GHz, suffering with only 256MB RAM.
PC I'll be designing for myself soon:
64-bit dual core Athlon processor
Dual SCSI 10kRPM low-latency RAID0, size doesn't really matter, I want speed
As much dual-channel DDR as the mobo can fit
Gigabit ethernet
I don't really care about graphics... I just want a generally fast box that I can program on, etc. Of course for these purposes this will be overkill, but I don't care