Ya - I love the trading feature. You can't sit there and propose all kinds of ridiculous trades. You get a bunch of reasonable offers, and then you have to counter realistically.
I completed one trade as the Bears yesterday, trading 31 year old TE Desmond Clark for draft picks. I had to pick between a 5th round pick in 2010 and a 5th round pick in 2009. I went with 2009. Trading Clark made a lot of sense, as Chicago has two young TEs, including Gregg Olson. A player like Clark is expendable, and is likely to have 5th round value.