In 10.04 the following drivers were available:
- nvidia-96 - GPUs ranging from GeForce series 2 (except for GeForce2 GTS/GeForce2 Pro, GeForce2 Ti and GeForce2 Ultra) to Geforce series 7 are supported
- nvidia-173 - GPUs ranging from GeForce series 5 to Geforce series 9 are supported
- nvidia-current (195) - GPUs such as GeForce series 6 or newer are supported
The compatibility notes are directly from the package description (should be 3rd paragraph) and haven't changed much in 12.04. It is worth noting that nvidia-current moved from 180 over to 185 and from there to 195 during the 10.04 life cycle.
Using nvidia-current might have worked very well in 10.04. But you have to understand how Nvidia maintains their proprietary drivers. This is not limited to Linux/Unix drivers and applies to Windows in a similar fashion and AMD/ATI is no different there.
For Linux, Nvidia maintains 3 versions of drivers: One for very old cards (2000-2005, I know that this is not exact, but let's try to keep it as simple as possible) with a very limited set of features, one for rather newer cards (2005-2010) with more features and one with support for the latest cards (2010 onward) and all features they provide. This is done to reduce the maintenance effort as much as possible. If implementing support for a new series or feature breaks support for older cards or makes them unstable, then this is a sacrifice to be made and users of those cards have to switch to an older but still maintained/compatible driver series.
Also you need to know a bit more about the particular chip. Wikipedia says it is a chip from 2007, however Geforce Series 7 was released in 2006 and most low end designs are based on the previous series or even earlier. So actually were talking about a low cost design from 2005 or 2004.
My advice in your case: Remove all old drivers and install the nvida-173 driver, it should be sufficient to run Compiz (I did that back in 2008 with 08.04, version back than was 140 or 160), however the chip may not be fast enough to run Unity, you could try to disable blur in CCSM, if that doesn't help you have to use Unity 2D.