Yea it's tough, those cares are really expensive. However, the new feature of Premiere CS5 is using Nvidia cards. The Youtube video below shows what could be done, but the Quadro fx 4800 card he's using costs over $1,000.
Here's a list of cards that are supported for doing this. I've read that Nvidia's new GPU's (ie - the GTX 480) would probably be supported later on in the year.
For Photoshop, I don't know if or how much the workstation cards will make a difference. At work or school, they use Macs so the GPU's in those are very weak compared to something like the Radeon 5870.







