I personally think the FA Cup winners should get the 4th champions league spot.
Wouldn't get many teams playing weakened sides then i reckon.
Just shows the pressure on clubs to stay in the premier league - making loads of changes for cup matches so as to keep their "best" players fit/fresh for the legue games.
Shame really , cos most of em have no chance of winning the league - so a cup is a realistic chance to get some silverware for the club and it's fans.
Never forget our league cup win in 2004 - and our UEFA cup run (to the final) in 2006.