This is a great question because I am in exactly the same situation.
My D30 is just sooo PERFECT for me but for the price, the 10D is latest science. I have added some fantastic "L" lenses over the years by not up-grading to the 10D or D60 but I will be forever curious about these bodies.
But, I'm still holding out for the $1,500 replacement to the 10D because the D30 is still my "one love" after the G1. And, of course, the price I paid for the D30 requires me to shut up and be happy. As long as the D30 does what you need to do, check the bet to the highest bidder and follow their reviews.
Chris