well my first DSLR was the predecessor of the 10D, called D60 which was a beauty to play with and i never upgraded it until i got the 40D (yes, that is quite a leap
Both will take very good pictures. And the 2 MP difference wont do much. But if you are looking at bargains why not see if you can't pick up a 20D or 30D? the 20D's is very cheap today aswell and is a much better camera than both the 10D and 350D combined.
Imho, if you are used to sturdier cameras, you will not be happy with the XXX series. God knows i prefere my 40D over my 450D any day of the week