Having used solidworks '99, solidworks 2001, solidworks 2001+ and solidworks 2003 on my system (with a Ti4200) id have to tell you that its all drivers. Im running solidworks doing entire KITCHENS and having no issues at all with my Ti fully hardware accelerated. Im using the 43.23 drivers. With the newer drivers, the performance is substandard and i get irregularities, but with these drivers i have no issues. Something to think about before blowing mega bucks on something you may not need

I can also tell you that for waterblock design and rendering, SOFTWARE acceleration is more than adequate

The only thing that the hardware rendering really helps in is when rotating the model - it appears smoother, and that is seriously the only difference i notice with it.
Im in favour of 2001 plus as its really great as far as system performance goes. 2003 is a bit of a whore actually (read: i bloody hate that version) because its far too intensive. The biggest bonus it has however is its input and output formats (which i believe are more than probably very important for what you) are very much improved through to programmes like autocad etc for output to programmes like cncmaster etc for cnc programming.
I hope this helps somewhat.
Edit - using 45.23's not 45.43