Why not put that to a test.To be honest, get nice glass over a nice body. A sharp lens can make an aging camera come back to life.
Suppose you own a Canon 350D with the too-cheap-for-words standard 18-55mm IS lens and you have something a bit short of a grand to spend. What would give you a better resolution (sharper pictures)?
Get the legendary super 17-55mm F2.8 lens for your 350D or get a new Canon 600D body (less expensive) with the same cheapo standard lens?
You can find the answer here.