Try going to Abenson's Greenhills (the one beside Chili's) sa corner ng Missouri and Connecticut. They have the 3 Samsung models side by side. I'm not sure though if they're all hooked up to one player. You could bring along some of your DVDs so you could compare them. If you want to compare them with the Philips, Abenson's Galleria has them side by side (along with the Toshiba and Sharp Aquos).
Like you, I was eyeing the Sony, Philips and Samsung before I decided to purchase the Philips 32PF7321 yesterday. I went with the Philips based on recommendations from a couple of PinoyDVD members (they said the Philips displayed cable tv broadcast better than the other two). This was a major factor for me because I want to use it to watch cable TV and not just with my DVD player and Xbox 360.
Regarding holding off the purchase - there will always be something new and prices will always drop.
I've read somewhere the difference between 720p and 1080p is not that noticeable for LCDs that are less than 40" so you might want to consider that as well in case you are only looking at getting a 32".