I'm using an nvidia geforce gt550 ti with hardware occlusion - (set for performance), with obge - (2 different types of AA, Crysis DOF, and godrays) + 1024x1024 textures, hi-rez bodies + faces and RTNM and lush and gaudy and natural environments and I get this:
http://i798.photobucket.com/albums/yy265/bassmunkee/Oblivion/niamh_ext_near_prison_sewer.jpg
Which seems perfectly reasonable to me, although it may give my GPU a cardiac arrest at some point in the future...

I was thinking of using the transparent anti-aliasing on the card but to be honest I really don't think I need it, card is running at 985 from 900 stock, about 54-55 centigrade after an hour's gaming, according to MSI Kombustor, anyway.

The 2xSSAA appears to be my favorite. Some of the higher sampling rats seem to use more of a blur effect than anything.
I'm not saying you don't have a legitimate reason, I'm just curious what that reason is, if I may ask? (For future purchase considerations on my part).

I set my Nvidia GTX470 to 2x AA for the same reason. Higher settings, despite doing a better job of jaggy reduction, added blurriness. I'm one who preferes crisp, sharp focused images. Therefore 2x AA is the best compromise for me.

I once tried an OBGE AA shader (?) that combined several different AA methods, applied at what I assumed were fairly high settings. I rather liked it. But in this case the performance drop was too severe.

-Decrepit-

I'm rocking the blurring

Me neither.

AA is too much fps drop for me