The best replacement for megaupload is mediafire.

The best alternatives to megaupload are rated as following:
★★★★★  mediafire
★★★★  rapidshare
★  filesonic
★  torrents
★  sendspace
★  megashares
★  megavideo
  newsgroups

Your alternative for megaupload is not listed? Suggest!
Speaking about megaupload, one probably shouldn't forget about idm.

Other search terms related to megaupload and their ratings are:
★★★★★ idm
★★★★ flashget
You have in mind a companion for megaupload and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of megaupload in all years. Click on graph for more.
megaupload
mediafire
rapidshare