It depends on how imporant the TV and video imprt functions are to you. The 9800SE AIW is great if you want to be able to watch TV and also import video from a number of sources. It has had a a number of reviews even in the SE version which are fairly good. They do make the point that the 9800SE AIW is not as impressive as an ordinary 9800 for 3d games.
My daughter actually has the 2600+MKR and I was really impressed with it. I can't tell you though how they two graphics cards compare and have had no luck yet in finding out!
Basically though I would suggest that if you want the TV and video import functions then that should steer you to the AIW, if that is not so important then a bit more research might be needed to compare the graphics cards in more detail.