to rake or not to rake, and how often?

Well, now autumn is arriving, and we have many trees.  What do you suggest about raking?  Is it good to rake frequently, infrequently, or not at all.  On one hand, I would think it would be good to just leave the leaves there to decompose by springtime.  On the other hand, I've heard (from non-organic gardeners) that its good to rake because you're then removing any dead grass, etc.  On the first hand again, I do like the way leaves look, and raking isn't exactly fun...  but, again, on the second hand, i guess i don't want them blowing around all season either.  What to do?

If the tree can smother the grass underneath it, it will have a better chance of out competing it.  On the other hand, the leaves will improve the soil in many ways.

If your trees are small or if your tree doesn't generate a lot of leaves, you can run a mulching mower over the leaves.  The pulverized leaves will feed the grass and the tree. 

If you have a LOT of leaves, the mulch can end up so thick that is can kill your lawn (and make your tree happy).  In this case, you probably want to rake a lot of the leaves.  These leaves are great for mulching gardens, shrubs, etc.  They are also great in your compost pile.