Haven't you gone from 500D - 7D - 1D MKIII in a year?
Now you want a 5D MKII?
Is it really that hard to stick with one for a while, I can't see the point in changing so quickly between them if you ask me.
Just my two cents.
EDIT: Infact, you've from from 500D - 7D - 1D MKIII in 5 months. And now want a 5D MKIII after 6 months?
I bought the 500D as my first DSLR (end of Oct last year) to see if it was for me (the DSLR way that is), quickly found out I did like it and that the 500D wasn't that great for sports or keeping up with the little 'un so I bought the 7D. More than happy with the 7D to be honest, but when the opportunity to trade for a 1D mkIII came along I went for it (after much agonising!). Not exactly a mindless rush for new kit, but I see where you're coming from. I don't believe I'll ever be a good photoghrapher no matter what kit I have, but the 1D sure helps offset my own lack of speed!

A 5D mkII won't suit me for sports or toddlers but I like what I see with FF. I've had a good look at the D700 reviews today but a whole change of system is a step to far, even for me

