Having spent time on all 3 islands I would go with Heimdall's
time line.

Samos is interesting (huge island) but well out of the mainstream.

IMHO Paros is far more interesting than Santorini - esp. when you
encounter the hordes of cruise ship denizens clogging up Fira.
But yes, the caldera view is stunning and unique - and romantic!

I've been reading the Rough Guide, Fodor's and DK Eyewitness travel. My husband and I would like to spend much of our time exploring Paros and Santorini and less time traveling to other islands. I'm leaning more towards a 5 night Paros/5 night Santorini split, with 2 nights in Athens. We do plan to visit Antiparos, since it's so close, and we'll certainly look into the Antiparos round-island boat trip. I'll check out the greek-islands website, too.

Again, trying to not repeat, Santorini is an unforgettable view and could be a 3-day visit. I personally would weight more days towards Paros as there are so many options to keep you as busy as you wish to be. If you like going to the beach, there are many beautiful ones on Paros.