I bought my 8800GTX in 11|2006 and have not upgraded since then.
You should check into nVidia's ability to do some DX 10.1 functions, more specifically those that involve AA.
"NVIDIA does enable developers to query their driver on support for a feature. This is how they can support multisample readback and any other DX10.1 feature that they chose to expose in this manner. Sure, part of the point of DX10 was to eliminate the need for developers to worry about varying capabilities, but that doesn't mean hardware vendors can't expose those features in other ways. Supporting DX10.1 is all or nothing, but enabling features beyond DX10 that happen to be part of DX10.1 is possible, and NVIDIA has done this for multisample readback and can do it for other things."