These are the facts:
1. CPU speeds are stalled.
2. Vista will run software slower.
3. The current workaround for speeding up most software is with multi-core CPUs.
4. Most software cannot be re-written for multi-core.
5. Even if it can, memory access will probably stall the software.
6. Going to 64-bit CPUs only helps software that works with extremely large datasets.
7. Going to high-speed GPUs (graphics boards) only works with graphics-intensive software.
Read it and weep: What's the story with Photoshop & multi-core? by John Nack of Adobe.