Well you see all versions will work for previous generations of Geforce cards no matter how old. You can pretty much use 51.75 on a TNT2. However, each generation will contain optimizations of some kind. These optimizations do not work perfectly for all generations.
45.23 and higher were all highly Geforce FX biased. They work well to get the FX cards score high in 3Dmark benchmarks and Aquamark 3 but actually have some bugs in real gaming. I'm sure you know Nvidia like to optimize for benchmarks. I've noticed that in real games the 44.03 drivers for Ti yield higher FPS with better image quality. If you're using Ti I wouldn't be using any other driver. The latest drivers have way too much optimizing in them and aren't that great FPS wise in games.
I highly recommend 44.03 if you like things to work like they should without subtle little bugs here and there that the new drivers have. I had a comparson a friend showed me that compared image differences between the latest and 44.03. LOTS OF BUGS!!! Too bad I lost the link.

Take my word for it tho mate.