Currently Being ModeratedMar 19, 2013 8:43 PM (in response to Sass)
The vast marjority of your songs will Match in the iTunes database, that is unless you have super rare music that doesn't already exist on iTunes, of course.
I recommend enabling iTunes Match and letting it do its thing. When it is done, most of your songs will be Matched and the rest will be Uploaded, so you can access all of them from all your devices. There could be a few that are ineligible depending on your library (songs that are too low quality can't be matched/uploaded, for example).
To find out which songs were Matched and which ones were Uploaded and if there were any problems, click Music > Songs then choose View > View Options and check iCloud Download and iCloud Status. Now you'll see the status of each song in those columns. You could sort the columns and set up Smart Playlists if you wanted.
I think you'll come to really like iTunes Match!