I am thinking of getting the 7D. I will keep the 30D and give the Xt to my great-nephew As far as lens go, I'm happy with what I have and don't plan to replace any of them.
But I would like to have a birding/wildlife lens. I was thinking of one of the following ones, Canon 300mm f/4L IS , 400mm 5.6L . I was even thinking about giving the 100-400mm another try. Maybe even the Sigma 150-500mm, but i'm not really sold on this one yet.
But i'm not going to pay the prices Canon are charging now. I could , but I won't !! And i'm not going to pay new prices for a used Canon lens.
But I've seen used Bigma going around $650 , which is not bad. In the winter I shoot out of my blind a lot, using a tripod. So i was thinking going this route and when the prices get back to normal. Sell it and get one of the above lens.
Or I could just keep using the 100-300mm f/4 with a tc, for awhile longer. It doesn't do a bad job.