I had been using the last few versions of Opera as the IE alternative. In fact the 9.63 and 9.64 releases are still backed up here along with Chrome which had replaced Opera. for a period of time until the RCs and the finished IE 8.
With IE 8 on both the XP mode and Vista run on a virtual HD as well both Opera and Chrome ended up being pushed aside to work with IE 8 on all three. I was pondering on taking a look at the next release of both until running across this.