I think so.
Aldo is in most peoples' p4p top 5, and if you include the WEC title he has reigned at fw since '09, going 6-0 since then.
Many people (not me, but many) think Edgar should still be the UFC lw champion, but either way he has proved to be a very high-level operator in his fights with Penn, Maynard and Henderson.
When was the last time two more decorated, more complete fighters met in the UFC?
Jones vs Shogun was a top fight, but Jones was only a contender then, whereas Aldo and Edgar are already championship calibre. Cain vs JDS was big, but again, JDS had no title pedigree at that time. Silva vs Sonnen II was a very high-profile fight, but IMO Sonnen is not on the Aldo/Edgar quality level, he's just a very effective mw wrestler.
Is Aldo vs Edgar a UFC superfight, the 2012 equivalent of GSP vs Penn?
I can't wait for this fight, expect it to be an absolute classic.