I have made a small list with the most common filehosts
Filehost:Highest Traffic Aug. 2011
Source:Alexa
59 Mediafire
61 Megaupload
71 4Shared
128 Fileserve
152 Rapidshare
159 Filesonic
173 Hotfile
309 Depositfiles
321 Wupload
568 videobb.com
654 Oron
779 Uploading.com
909 putlocker.com
934 Uploaded.to
1013 Freakshare
1145 Sendspace
1207 Userporn.com
1280 Duckload
1309 Easy-Share
1991 Netload
8813 Megashares
21906 filefat.com
24230 filepost
Filehost:Highest Traffic Aug. 2011
Source:Alexa
59 Mediafire
61 Megaupload
71 4Shared
128 Fileserve
152 Rapidshare
159 Filesonic
173 Hotfile
309 Depositfiles
321 Wupload
568 videobb.com
654 Oron
779 Uploading.com
909 putlocker.com
934 Uploaded.to
1013 Freakshare
1145 Sendspace
1207 Userporn.com
1280 Duckload
1309 Easy-Share
1991 Netload
8813 Megashares
21906 filefat.com
24230 filepost