Why are you thinking of making a change? Is there something about the Nikon with which you are not happy? There isn't a whole lot of difference between the two systems. The 80-200 is a nice lens too, although I've not used to push-pull version. I have the two-ring version.
If you're just bored, try picking up a book on a different type of technique or subject, and practice shooting that. The 80-200 2.8 would be good for shooting pics of hookers on the strip at night.....
1999 e46 328i Ti Silver / Black[retired]
2007 e90 335xi Jet Black / Black[retired]
2011 e70 X5 35d Vermillion Red / Cinnamon
2011 e92 M3 LeMans / Fox Red extended