According to VGChartz, 360 has a ~1,600,000 lead according to software sales. I don't know how the big titles will sell this year (Halo: Reach, GT5 etc.) but I think that by the end of the year, the software sales between the two consoles will be very close (well, at least closer than the ~22,000,000 lead the 360 had last year).
Time will tell.