Leaves are good for soil so sure you can leave them there. Whole leaves tend to mat and clump together though. Not really a big deal over the winter, but they have to be raked up come spring to plant in the soil.

One method that removes the need for a rake is to run the leaves over with a lawn mower. A mulch mower works best, but a regular mower does the same thing with a few passes. Just chop them up and leave them lay. They will decompose and help the soil.

On a lawn you want to limit the leaves so they aren't so thick they smother the turf, but in the garden they can be as thick as you want.

The leaves that fall from the trees growing in my yard get mulch mowed back into the soil they came from to feed the soil the trees are growing in. I pick up leaves on excursions to town to shred for mulching my planting beds and to make compost. As justaguy indicated whole leaves tend to matt together and make a somewhat impervious barrier to plant growth and if possible you should shred those leaves some way. A rotary mower is a fairly good machine to use for that if some simple precautions are taken first. You do need a fairly solid stand for the mower, blocks ot keep the mower from moving without interfering with raking the leaves under the mower deck. A means of catching the leaves as the mower mulches them, a cage of some kind, or a bag on the mower so you can pick them up as you mow so you need not rake them.

I leave my leaves right where they fall. If they are in the way when I go to plant is spring I rake them out of the way a bit and then go back ignoring them.

Unfortunately my leaves don't fall in the garden, so we rake them and put the in big (5') garden fence rings off to the side of the lawn. Let them sit 2 season, and you have beautiful leaf mold for hanging pots, etc.

I love leaves.

Especially my neighbors leaves.

Mine get mulch mowed but the neighbors don't like theirs so I rake them for them and use them to winter mulch many of my shrubs ect. And to add to the compost bin.

I love leaves. :)