Stephen,I have a 50D,and I would be happy to recommended it!
It takes a little while to get use to,but you will find it very useful-I have not used it for a great deal of astronomy yet,the astro work I have done with it has been good.
The lens you mention the 15-85 will be ideal for you and your camping trips and kids etc.
I got the 17-55 F 2.8 IS lens,as I wanted F 2.8,but did consider the 15-85.it very good,You will not go wrong gettting the combo you mention above.
The only thing,get it NOW!,I think they now have discontinued 50D,and the prices the had them for while still available was very good! around $1000!
I was nearly thinking of buying a second as back up,I agree movie mode is something I did not want.the PS have movie mode for quick movies.
hope this helps.cheers Chris