What software to use with Canon 500D?
If you shoot in RAW I can recommend Lightroom, which I am using. If you are not shooting RAW the benefit of using Lightroom is somewhat less...
I use the import function in Lightroom to copy directly from the CF card in my camera, and I organize my files in certain folders on my harddrive! (You can choose where to import to in Lightroom)
You can try Lightroom for free for 30 days.