Personally, i think the Honda Pilot is an excellent choice. Quality issues should be gone since it is not a brand new model. It would be my favorite choice for your parents, based on room, safety, quality, reliability, and performance.
Other choices have been mentioned. I kinda always like the GMC Envoy for some odd reason...maybe the engine attracts me.
I never warmed up to the Explorer...the interior is just plain cheap! The exterior is attractive...however, the rear suspension is a horrible design (for me)!
Another possible choice is the upcoming redesign 4Runner, which should have as much room as the GX470 (8 people). The next generation RX is not going to be redesigned within THIS year...maybe mid- or late 2003. I heard the 4Runner is coming out this fall.