How technically competent are you?  Can you put a system together from separate components, or are you looking for ready made system that encompasses components that us "experts" recommend?  I can tell you that OpenGL will have no impact on your 2D performance, so don't spend a lot of money on an OpenGL Video Card, unless you do your texture work in 3D.  I'm not sure about your 3D apps.

If your new computer is your only computer, I recommend that you buy a system with 2 large Hard Drives in RAID 1 Configuration.  A large External Hard Drive for backup is also recommended.  Nothing is more important than your work!!

I plan to upgrade the motherboard, processor, and possibly the video card of my present system.  Right now my new component choices are: Athlon 64x2 4200 Processor and ASRock 939Dual-SATA2 Motherboard.  I plan to re-use these components in my present system:

1GB Corsair PC400 DDR Memory, LG Electronics GSA-4163B DVD RW Drive, ATI Radeon 9800 Pro Video Card, Hauppauge PVR-150 TV Card, 2 Maxtor 120GB Harddrives in RAID 1 Configuration.